2008 through 2010 South Coast Air Quality Management District (SCAQMD) Upper-Air Station Data Summary

Transcription

1 2008 through 2010 South Coast Air Quality Management District (SCAQMD) Upper-Air Station Data Summary Data Summary Prepared for South Coast Air Quality Management District Diamond Bar, CA August 2011

2 This document contains blank pages to accommodate two-sided printing.

3 2008 through 2010 South Coast Air Quality Management District (SCAQMD) Upper-Air Station Data Summary Data Summary STI Prepared by Charley A. Knoderer Kevin M. Smith Clinton P. MacDonald Dianne S. Miller Sonoma Technology, Inc N. McDowell Blvd., Suite D Petaluma, CA Ph F sonomatech.com Prepared for Kevin Durkee South Coast Air Quality Management District Copley Drive Diamond Bar, CA August 3, 2011 Cover graphic shows the Irvine wind profiler site.

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5 Table of Contents Table of Contents Section Page List of Figures... iv List of Tables... vi 1. Operations Summary Overview RWP/RASS Background MiniSODAR Background Surface Meteorological Background Data Summary Diurnal Averages Wind Roses Data Completeness and Recovery Periods of Operation Data Completeness Data Recovery Conclusions and Recommendations References Appendix A: Diurnal Wind Averages... A-1 : Wind Roses... B-1 iii

6 List of Figures List of Figures Figure Page 1-1. Map showing locations of upper-air stations throughout the Los Angeles Basin Diurnally averaged winds at LAX by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins Diurnally averaged T v profiles at LAX by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins Diurnally averaged winds at Whiteman by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins Diurnally averaged winds at Irvine by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins Diurnally averaged winds at Ontario by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins Diurnally averaged winds at Moreno Valley by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins Surface wind rose for Los Angeles International Airport for the period from January 1, 2010, through December 31, 2010, at 10 m agl Wind roses for Los Angeles International Airport for the period from January 1, 2010, through December 31, 2010, for the 0 to 200 m agl height bin and the 1000 to 1200 m agl height bin RWP wind roses for Los Angeles International Airport for the period from December 1, 2009, through February 28, 2010; March 1, 2010, through May 31, 2010; June 1, 2010, through August 31, 2010; and September 1, 2010, through November 30, 2010, for the 0 to 200 m agl height bin Surface wind rose for Moreno Valley for the period from January 1, 2010, through December 31, 2010, at 10 m agl RWP wind roses for Moreno Valley for the period from January 1, 2010, through December 31, 2010, for the 0 to 200 m agl height bin and the 1000 to 1200 m agl height bin RWP wind roses for Moreno Valley for the period from December 1, 2009, through February 28, 2010; March 1, 2010, through May 31, 2010; June 1, 2010, through August 31, 2010; and September 1, 2010, through November 30, 2010, for the 0 to 200 m agl height bin Periods of operation and downtimes for RWP wind and RASS T v data for the period from January 1, 2008, through December 31, iv

7 List of Figures Figure Page Periods of operation and downtimes for minisodar wind data for the period from January 1, 2008, through December 31, Periods of operation and downtimes for minisodar wind data for the period from January 1, 2009, through December 31, Periods of operation and downtimes for minisodar wind data for the period from January 1, 2010, through December 31, Periods of operation for surface meteorological parameters for LAX for the period from January 1, 2008, through December 31, Periods of operation for surface meteorological parameters for Ontario for the period from January 1, 2008, through December 31, Periods of operation for surface meteorological parameters for Moreno Valley for the period from January 1, 2008, through December 31, Periods of operation for surface meteorological parameters for Whiteman for the period from January 1, 2008, through December 31, Periods of operation for surface meteorological parameters for Irvine for the period from January 1, 2008, through December 31, RWP wind data completeness for the period from January 1, 2008, through December 31, 2010, for Whiteman, Irvine, LAX, Ontario, and Moreno Valley RASS T v data completeness for the period from January 1, 2008, through December 31, 2010, for Whiteman, Irvine, LAX, Ontario, and Moreno Valley MiniSODAR wind data completeness for the period from January 1, 2008, through December 31, 2010, for Whiteman, Irvine, LAX, and Ontario RWP wind data recovery for the period from January 1, 2008, through December 31, 2010, for Whiteman, Irvine, LAX, Ontario, and Moreno Valley RASS T v data recovery for the period from January 1, 2008, through December 31, 2010, for Whiteman, Irvine, Ontario, and Moreno Valley MiniSODAR wind data recovery for the period from January 1, 2008, through December 31, 2010, for Whiteman, Irvine, LAX, and Ontario v

8 List of Tables List of Tables Table Page 1-1. Site locations and elevations Specifications of the upper-air meteorological equipment Specifications of the surface meteorological equipment vi

9 Operations Summary 1. Operations Summary The South Coast Air Quality Management District (SCAQMD) operates five 915-MHz radar wind profilers (RWP) with Radio Acoustic Sounding Systems (RASS), four minisodars, and five surface meteorological stations in the Los Angeles Basin, as shown in Figure 1-1. These instruments provide continuous vertical profiles of wind and virtual temperature (T v ) and backscatter data that can be used to derive mixing heights. Data from the instruments are used by SCAQMD to support the Photochemical Assessment Monitoring Stations (PAMS) program. Sonoma Technology, Inc. (STI) and its subcontractor, Technical and Business Systems, Inc., maintain the instruments for SCAQMD. This report provides background information about the instruments and the measurements collected from January 1, 2008, to December 31, Instrument operations are ongoing. Figure 1-1. Map showing locations of upper-air stations throughout the Los Angeles Basin. All five sites include surface meteorological measurements. 1-1

10 Operations Summary 1.1 Overview Table 1-1 lists the measurement site locations and elevations. These sites were selected, within logistical constraints, to cover different anticipated flow patterns throughout the Los Angeles basin and to minimize potential instrument interferences. Tables 1-2 and 1-3 list the specifications of the upper-air and surface meteorological instruments at the sites. Table 1-1. Site locations and elevations. Site Latitude ( N) Longitude ( W) Elevation (m) Los Angeles (LAX) Whiteman (WHP) Irvine (IRV) Ontario (ONT) Moreno Valley (MOV) Table 1-2. Specifications of the upper-air meteorological equipment. Measured Parameter Sensor Manufacturer Sensor Model Sensor Specifications Maximum Vertical Range Vertical Data Interval RWP wind speed Vaisala Meteorological Systems LAP-3000 Accuracy: ±1.0 m/s Range: 0 to ~56 m/s horizontal speed Minimum range: 130 m Maximum range: 4000 m Reporting intervals Low mode: 60 m High mode: 96 m Minimum range: 130 m RWP wind direction Vaisala Meteorological Systems LAP-3000 Accuracy: ±10 Range: 0 to 360 Maximum range: 4000 m Reporting intervals Low mode: 60 m High mode: 96 m RASS virtual temperature Vaisala Meteorological Systems LAP-3000 Accuracy: ±1.0 C Range: 0 to 40 C Minimum range: 130 m Maximum range: 1500 m Reporting intervals: 62 m MiniSODAR wind speed Atmospheric Systems Corporation Model 4000 Accuracy: ±0.5 m/s Range: 0 to 45 m/s Minimum range: 30 m Maximum range: 200 m Reporting intervals: 10 m MiniSODAR wind direction Atmospheric Systems Corporation Model 4000 Accuracy: ±5 Range: 0 to 360 Minimum range: 30 m Maximum range: 200 m Reporting intervals: 10 m 1-2

11 Operations Summary Measured Parameter Table 1-3. Specifications of the surface meteorological equipment. Sensor Manufacturer Sensor Model Wind speed R.M. Young 5305-AQ Wind direction R.M. Young 5305-AQ Sonic wind speed Sonic wind direction Sonic wind speed Sonic wind direction Temperature a Relative humidity a Met One Met One 035A 035A Met One Met One Vaisala Meteorological Systems Vaisala Meteorological Systems HMP45AC HMP45AC Pressure Met One 090D Solar radiation Kipp & Zonen CM6B Solar radiation Licor LI200 Ultraviolet radiation Eppley Labs TUVR a Includes aspirated radiation shield (R.M. Young 43502). Sensor Specifications Accuracy: ±0.2 m/s Range: 0 to 50 m/s Starting threshold: 0.4 m/s Accuracy: ±3 Range: 0 to 360 Starting threshold: 0.5 m/s Accuracy: ±0.2 m/s <11.3 m/s or ±2% >11.3 m/s Range: 0 to 50 m/s Accuracy: ±3 Range: 0 to 360 Accuracy: ±1% RMS ±0.05 m/s (0 to 30 m/s) or ±3% (30 to 40 m/s) Range: 0 to 40 m/s Accuracy: ±2 (1 to 30 m/s) ±5 (30 to 40 m/s) Sites with Sensor LAX, ONT, MOV, WHP, IRV LAX, ONT, MOV, WHP, IRV LAX LAX ONT ONT Range: 0 to 360 Accuracy: ±0.5 C LAX, ONT, MOV, Range: -40 to 60 C WHP, IRV Accuracy: ±2% LAX, ONT, MOV, Range: 0.8% to 100% WHP, IRV Accuracy: ±1.35 mb LAX, ONT, MOV, Range: 880 to 1084 mb WHP, IRV Accuracy: ±5% LAX, ONT, Range: W/m 2 MOV, IRV Accuracy: ±5% LAX, Range: W/m 2 MOV, WHP, IRV Accuracy: ±5% LAX, ONT, Range: 0-70 W/m 2 WHP, IRV To optimize data resolution, the RWPs are configured to cycle in low and high operational modes. In low operational mode, the RWPs measured winds from about 130 m above ground level (agl) to about 1,600 m agl with a vertical resolution of about 60 m. In high operational mode, the RWP measurements covered a greater altitude range, from about 300 m agl to about 3,000 to 4,000 m agl, with a coarser vertical resolution of 96 m. The exact height coverage and data completeness depend on atmospheric conditions. Wind data from both 1-3

12 Operations Summary modes are merged to create a single profile with 60-m resolution below 800 m agl and 96-m resolution at 800 m agl and above. All diurnal averages and wind roses are calculated using 200 m height bins. The RASS systems measure T v for the first five minutes of each hour. Virtual temperatures are measured from about 130 m agl to about 1,600 m agl with 62-m vertical resolution. The T v is the temperature that a dry parcel of air would have if its pressure and density were equal to that of a moist parcel of air. The minisodars are configured to measure winds from 30 m agl up to about 200 m agl with a vertical resolution of 10 m. All diurnal averages and wind roses are calculated using 10 m height bins. The surface meteorological towers are configured to measure wind speed and wind direction using an aerovane-type wind speed sensor at 10 m agl. Air temperature, relative humidity, solar radiation, ultraviolet radiation, and pressure were measured at about 4 m agl. The Ontario and LAX sites are also configured to measure wind speed and wind direction using sonic anemometers at 10 m agl. Audits have been performed at all five sites within the last two years. Audits were performed in June 2009 at WHP, ONT, and IRV; in June 2010 at MOV; and in November 2010 at LAX sites. Audit results are available via the e-site log at or upon request from SCAQMD. 1.2 RWP/RASS Background An RWP with RASS system consists of a single phased-array antenna. In this phased-array design, the radar beam is electronically pulsed vertically, and in two orthogonal directions (23 from the vertical). Phased-array systems include electronic subsystems that control the RWP s transmission, reception, and signal processing functions. For wind measurements, the RWP transmits an electromagnetic pulse along each of the beam directions, one at a time. The duration of the transmission determines the length of the pulse emitted by the antenna, which, in turn, corresponds to the volume of air illuminated (in electrical terms) by the radar beam. These electromagnetic signals are then scattered by small-scale turbulent fluctuations that induce irregularities in the electromagnetic refractive index of the atmosphere. A receiver measures the small amounts of the transmitted energy that are scattered back toward the RWP (referred to as backscattering ). These backscattered signals are received at a slightly different frequency than the transmitted signal. This difference is called the Doppler frequency shift and is directly related to the velocity of the air moving toward or away from the RWP along the direction the beam is pointing. The radial velocity measured by the tilted beams is the vector sum of the horizontal motion of the air toward or away from the RWP plus any vertical motion present in the beam. Using appropriate trigonometry, we can calculate the three-dimensional meteorological velocity components (u, v, w) and wind speed and wind direction from the radial velocities. A minimum of 60% of the data collected during an hour must fall within a particular range of values in order for these values to be valid for determining the hourly average. 1-4

13 Operations Summary The RASS measurement components consist of four vertically pointing acoustic sources (which are equivalent to high-quality loudspeakers) placed around the radar antenna and an electronics subsystem consisting of an acoustic power amplifier and signal-generating circuit boards. The acoustic sources are enclosed by noise-suppression shields to minimize nuisance effects that might bother nearby neighbors. Each acoustic source transmits approximately 75 watts of power and produces acoustic signals in approximately the 2020-Hz to 2100-Hz range. The RASS operates on the principle that when the wavelength of the acoustic signal matches the half wavelength of the radar (called the Bragg match), enhanced scattering of the radar signal occurs. During RASS operation, acoustic energy transmitted into the vertical beam of the radar produces the Bragg match and allows the RWP to measure the speed of the acoustic signals. Because the speed of sound varies with temperature and altitude, T v profiles can be calculated from these measurements. 1.3 MiniSODAR Background The minisodar uses an observational process similar to that of the RWP except that the sodar uses pulses of sound instead of electromagnetic energy. The minisodar detects the returned acoustic energy scattered from air density fluctuations caused by turbulence. It provides 15-minute averaged wind speed and direction up to a 200-m agl maximum range with a lowest sampling height of approximately 30 m agl and a vertical resolution of about 10 m. The raw sampling rate is one wind sample every three seconds. Each sample undergoes internal checks (signal-to-noise criteria, etc.) to confirm its validity. 1.4 Surface Meteorological Background The surface meteorological data acquisition systems consist of Campbell Scientific, Inc., model CR1000 data loggers. The data loggers sample the meteorological sensor outputs once every second, convert the outputs to physical parameter units, and produce 5-minute, 60-minute, and 24-hour averages of each parameter. Wind speed and direction were reported as measured (e.g., no special algorithms were applied when the wind speeds were reported below the instrument starting threshold). For example, a 60-minute average could have a mix of 5-minute wind speeds sampled at 0 m/s and 5-minute wind speeds above the instrument s starting threshold of 0.4 m/s, resulting in a 60-minute average lower than the starting threshold. Standard deviations were also computed for wind speed and direction variables. The standard deviations of the wind direction (sigma theta) data were computed following U.S. Environmental Protection Agency s Meteorological Monitoring Guidance for Regulatory Modeling Applications (U.S. Environmental Protection Agency, 2000) and the Quality Assurance Handbook for Air Pollution Measurement Systems, Volume IV: Meteorological Measurements Version 2.0 (U.S. Environmental Protection Agency, 2008). The averages were calculated using Campbell Scientific s EPA Wind Vector option, which includes mean horizontal wind speed (scalar), unit vector mean wind direction, and sigma theta (using the Yamartino algorithm). In addition, resultant wind speed and direction averages were calculated. 1-5

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15 Data Summary 2. Data Summary The data summary includes diurnal averages of winds and temperatures, wind roses, and data completeness and data recovery statistics for the RWP, minisodar, and surface meteorological instruments for the period from January 1, 2008, through December 31, 2010, for all five upper-air sites. 2.1 Diurnal Averages Diurnal averages are averages of a parameter (such as wind speed and direction) calculated throughout a given period of time (such as a year) for each hour of the day. These averages provide information about general flow patterns and also help identify instrument issues. Diurnal averages were calculated on the RWP winds, minisodar winds, surface winds, and RASS virtual temperatures on an annual basis. The RWP winds and RASS virtual temperatures were calculated in 200 m height bins, while the minisodar winds were calculated in 10 m height bins. Note that the 0 to 200 m agl bin from the RWP includes data from the RWP s first range gate, which is typically around 130 m agl. The surface wind averages were calculated from measurements made at 10 m agl. Note that all diurnal wind averages were calculated using vector-averaging, which inherently reduces wind speed. Diurnal average calculations require a completeness of 50% for each height for each period of time. Multiple data gaps during the seasons made it infeasible to calculate the averages for all seasons. All available diurnal averages are provided in Appendix A. Examples of diurnal winds and a diurnal T v average are discussed in this section. The diurnal averages shown provide a climatology of wind and T v profiles throughout the year for each site. They also show how complex terrain can affect the wind and T v patterns throughout the Los Angeles basin. Appendix A contains the diurnal averages for all of the SCAQMD upper-air sites for winds and T v. 2-1

16 Data Summary Figure 2-1 shows the diurnal average wind profiles for LAX from January 1 through December 31, Below about 1200 m agl, the average wind profiles are observed to be offshore until about 0800 to 1000 Pacific Standard Time (PST). The average wind profiles then become onshore until about 2200 PST, when they switch back to offshore. Above about 1200 m agl, the average wind profiles are generally northwesterly (onshore). Figure 2-1. Diurnally averaged winds at LAX by height and time for the period from January 1, 2010, 1 through December 31, 2010, in 200 m bins. 1 The incorrect dates that appear within the wind profile and wind rose figures are automatically generated by the LAPDat software for the complete data set being used and do not reflect the date range of the data used to generate the figure. The date in the figures upper right corner is correct. 2-2

17 Data Summary Figure 2-2 shows the diurnal average T v profiles for LAX from January 1 through December 31, In general, the average T v profiles do not exhibit a large variation, because of the site s proximity to the Pacific Ocean. However, the temperature inversion base of about 500 m agl observed near 1000 PST is consistent with the top of the nocturnal boundary layer as indicated by the onshore flow observed in Figure 2-1. Figure 2-2. Diurnally averaged T v profiles at LAX by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins. 2-3

18 Data Summary Figure 2-3 shows the diurnal average wind profiles for Whiteman from January 1 through December 31, Below about 1000 m agl, the average wind profiles are observed to be easterly until about 0900 to 1000 PST. The average wind profiles then become generally southerly until about 1800 PST, when they switch back to easterly. Notice that beginning around 1500 PST, some mixing of westerly flow can be seen in the 500 m agl to 1200 m agl layer. Above about 1400 m agl, the average wind profiles are westerly. Figure 2-3. Diurnally averaged winds at Whiteman by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins. 2-4

19 Data Summary Figure 2-4 shows the diurnal average wind profiles for Irvine from January 1 through December 31, Below about 1000 m agl, the average wind profiles are observed to be south-southeasterly from about 0000 to 1000 PST and again from about 2000 to 2300 PST. Note that a layer (between about 550 m to 1300 m agl) of southeasterly winds persists from 1000 to about 1300 PST. The average wind profiles become generally west-southwesterly from about 1000 to 1900 PST. Above about 1400 m agl, the average wind profiles are generally westerly. Figure 2-4. Diurnally averaged winds at Irvine by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins. 2-5

20 Data Summary Figure 2-5 shows the diurnal average wind profiles for Ontario International Airport from January 1 through December 31, Below about 1100 m agl, the average wind profiles are observed to be southwesterly from about 0000 to 0300 PST, switching to east-southeasterly at 0400 PST. The average wind profiles become west-southwesterly beginning around 0900 PST near the surface to as late as 1100 PST at about 850 m agl, representing the onset and growth of onshore flow. The west-southwesterly flow persists overnight until roughly 0300 PST. Above about 1400 m agl, the average wind profiles are generally west-southwesterly. Figure 2-5. Diurnally averaged winds at Ontario by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins. 2-6

21 Data Summary Figure 2-6 shows the diurnal average wind profiles for Moreno Valley from January 1 through December 31, Below about 800 m agl, the average wind profiles are observed to be east-southeasterly from about 0000 to 0900 PST. The average wind profiles become northwesterly beginning around 1100 PST and lasting through about 2000 PST. The average wind profiles transition from northwesterly back to easterly between 2100 and 2300 PST. Above about 1000 m agl, the average wind profiles are generally westerly; however, from 0900 to about 1600 PST, the average wind profiles shift to southwesterly. Figure 2-6. Diurnally averaged winds at Moreno Valley by height and time for the period from January 1, 2010, through December 31, 2010, in 200 m bins. 2.2 Wind Roses Wind roses provide a view of the distribution of wind speed and direction at a particular site over a defined period of time. Wind roses were created using the LAPDat software package (which SCAQMD owns). Wind roses for the RWP, minisodar, and surface winds were created annually for each site for the period from January 1, 2008, through December 31, 2010; seasonal plots were created for the period from December 1, 2007, through November 30, RWP wind roses were created in 200 m bins at three different levels; 0 to 200 m agl (nominal), 1000 to 1200 m agl, and 2000 to 2200 m agl. Note that the 0 to 200 m agl bin includes data from the RWP s first range gate, which is typically around 130 m agl. MiniSODAR wind roses were created in 100 m bins at the 0 to 100 m agl level. Surface wind roses were created at 10 m agl. All wind roses are presented in. Some examples are shown 2-7

22 Data Summary in this section. While these wind roses show differences, on average, at different levels in the atmosphere, it is also important to understand that they do not capture the day-to-day differences that could affect pollutant transport within the Los Angeles basin. The differences observed in the wind roses at different levels throughout the years show why it is important to have continuous upper-air measurements, particularly in regions with complex topography. Figure 2-7 shows an example of a surface wind rose for LAX for the period of January 1 through December 31, Notice that the winds are predominantly from the west-southwest. Figure 2-8a shows a RWP wind rose for the 0 to 200 m agl bin for LAX during the same period. Notice that wind speeds were, on average, stronger at the surface than within the 0 to 200 m agl bin of the RWP, which generally represents a few hundred meters above the surface. Figure 2-8b shows the annual RWP wind rose for the 1000 to 1200 m agl bin for LAX during the same period. This wind rose shows that winds at about 1000 to 1200 m agl were northwesterly almost 40% of the time and southeasterly about 30% of the time. This is in contrast to the 0 to 200 m agl level, where winds were predominantly from the west-southwest because of the sea breeze. Figure 2-7. Surface wind rose for Los Angeles International Airport for the period from January 1, 2010, through December 31, 2010, at 10 m agl. 2-8

23 Data Summary Figure 2-8. Wind roses for Los Angeles International Airport for the period from January 1, 2010, through December 31, 2010, for (a) the 0 to 200 m agl height bin and (b) the 1000 to 1200 m agl height bin. 2-9

24 Data Summary Figure 2-9 shows the RWP wind roses at LAX broken down by the winter, spring, summer, and fall seasons of 2010 for the 0 to 200 m agl bin. The winds were westsouthwesterly approximately 40% of the time. However, during the summer, the flow was westsouthwesterly about 60% of the time because of the stronger summertime sea breeze. Figure 2-9. RWP wind roses for Los Angeles International Airport for the period from (a) December 1, 2009, through February 28, 2010; (b) March 1, 2010, through May 31, 2010; (c) June 1, 2010, through August 31, 2010; and (d) September 1, 2010, through November 30, 2010, for the 0 to 200 m agl height bin. Note that the rings for the summer season range from 0 to 50%, whereas the rings for the other seasons range from 0 to 25%. 2-10

25 Data Summary Figure 2-10 shows an example of a surface wind rose at 10 m agl for Moreno Valley for the period of January 1 through December 31, The predominant wind flow during 2010 was from the northwest, with a secondary maximum from the southeast. Figure 2-11 shows the wind roses at Moreno Valley for the 0 to 200 m agl height bin and the 1000 to 1200 m agl height bin of the RWP for the same period. Notice that the surface wind speeds shown in Figure 2-10 are stronger, on average, than the 0 to 200 m agl winds shown in Figure 2-11a, as was observed at LAX. Despite this difference in wind speeds, the wind directions, on average, are similar at both levels. At the 1000 to 1200 m agl height bin, the winds were predominantly out of the south through west (or the 180 through 270 quadrant) approximately 50% of the time, in contrast to the predominantly northwest and southeast flows observed near the surface. Figure Surface wind rose for Moreno Valley for the period from January 1, 2010, through December 31, 2010, at 10 m agl. Figure RWP wind roses for Moreno Valley for the period from January 1, 2010, through December 31, 2010, for (a) the 0 to 200 m agl height bin and (b) the 1000 to 1200 m agl height bin. 2-11

26 Data Summary Figure 2-12 shows the RWP wind roses at Moreno Valley at the 0 to 200 m agl height bin, broken down by the winter, spring, summer, and fall seasons for During winter 2010, winds were predominantly out of the east through southeast, while northwesterly winds were most common during the remaining seasons. This is consistent with the land being cooler than the ocean during the winter, resulting in more days with flow towards the Pacific Ocean. Figure 2-12a also shows a higher occurrence of offshore flow at Moreno Valley during the winter than during other seasons, consistent with the pattern observed at LAX. Figure RWP wind roses for Moreno Valley for the period from (a) December 1, 2009, through February 28, 2010; (b) March 1, 2010, through May 31, 2010; (c) June 1, 2010, through August 31, 2010; and (d) September 1, 2010, through November 30, 2010, for the 0 to 200 m agl height bin. 2-12

27 Data Summary 2.3 Data Completeness and Recovery The periods of operation, data completeness, and data recovery of the upper-air winds, T v, and surface meteorological data were determined for all instruments. Periods of operation are defined as those times when the instruments were operational; whereas downtimes are those times when the instruments were not operational. Data completeness is a measure of the number of points received at each height versus the number of points possible at each height and includes downtimes. Data recovery is a measure of the number of data points received at each height versus the number of points possible at each height and does not include instrument downtimes Periods of Operation Figure 2-13 shows the periods of operation and downtimes for the RWP and RASS from 2008 through The causes of the downtimes are shown in Figure 2-13 and were mostly related to hardware failures. There were two non-hardware related downtimes: (1) the Moreno Valley site was moved about 100 yards because of construction at the water treatment facility, requiring a new foundation and power installation, and (2) the air conditioner failed at Ontario in March 2010, requiring the site operator to shut down the RWP and RASS when temperatures were high. LAX MOV ONT IRV WHP Whiteman installed 4/17/2008 Audio amplifier Phase shifter PIRAQ board Phase shifter RWP shut off and moved Radar processor RWP processor RWP processor shut off due to failed AC Power supply & hard drive RWP shut off for facility power cut-over Power supply Loose RWP cable connection new cables ordered Figure Periods of operation and downtimes for RWP wind and RASS T v data for the period from January 1, 2008, through December 31,

28 Data Summary Figures 2-14, 2-15, and 2-16 show the periods of operation and downtimes for the minisodars for 2008, 2009, and 2010, respectively. Causes for downtimes are shown in the figures. Note that the Whiteman minisodar was installed on April 17, 2008, and experienced several problems initially with the power management module. The Irvine minisodar was installed on May 16, There were several periods from 2008 through 2010 for which data are missing. These figures show all data that are available after downloading data directly from the minisodars and from SCAQMD s servers. The primary reasons for the missing data were communications failures with the minisodars and a lack of proper back-ups. Back-up flash drives were installed earlier this year to mitigate loss of data. Power Management Issue through 8/7/08 Sodar installed 8/7/08 Whiteman installed 4/17/08 Communications Communications Communications Communications Sodar at ASC for repairs Sodar hard drive Communications Figure Periods of operation and downtimes for minisodar wind data for the period from January 1, 2008, through December 31,

29 Data Summary sodar removed for repairs Communications Communications ASP removed for upgrades Communications sodar PC ASP removed for upgrades Figure Periods of operation and downtimes for minisodar wind data for the period from January 1, 2009, through December 31, Irvine sodar installed Communications Sodar upgrades at ASC Miscellaneous log-in issues Sodar upgrades at ASC Communications Sodar PC Sodar upgrades at ASC Communications Figure Periods of operation and downtimes for minisodar wind data for the period from January 1, 2010, through December 31,

30 Data Summary Figures 2-17 through 2-21 show the periods of operation for the instruments measuring surface meteorological parameters at LAX, Ontario, Moreno Valley, Whiteman, and Irvine. Note that the Moreno Valley surface tower was removed during late 2007 in advance of plans to move the site about 100 yards south because of construction at the water treatment plant and was not reinstalled until August 7, The Whiteman surface tower installation was not completed until August 4, Figure Periods of operation for surface meteorological parameters for LAX for the period from January 1, 2008, through December 31,

31 Data Summary Figure Periods of operation for surface meteorological parameters for Ontario for the period from January 1, 2008, through December 31, Surface tower installation completed August 7, 2008 Figure Periods of operation for surface meteorological parameters for Moreno Valley for the period from January 1, 2008, through December 31,

32 Data Summary Surface tower installation completed August 4, 2008 Figure Periods of operation for surface meteorological parameters for Whiteman for the period from January 1, 2008, through December 31, Figure Periods of operation for surface meteorological parameters for Irvine for the period from January 1, 2008, through December 31,

33 Data Summary Data Completeness Figure 2-22 shows the RWP wind data completeness by height by time of day for all five sites. Recall that the low mode and high modes were merged at 800 m agl. Data completeness includes downtimes; as a result, the maximum data completeness at some sites, such as Irvine, was only about 70% to 80%. Considering the downtimes due to instrument failures, the data completeness was good at all sites. In general, data completeness was highest at the lowest altitudes, as is expected because the radar signal returns diminish as the distance from the RWP increases. In general, the data completeness at altitudes above about 1000 to 1500 m agl was lower during the morning hours than during the afternoon hours. This may be due to the generally drier air found above the temperature inversions that typically set up each morning. Recall that dry air has fewer humidity gradients, hence fewer reflectivity targets and less chance of a return signal making it back to the RWP. Figure 2-23 shows the RASS T v data completeness by height and by time of day. The low data completeness at Whiteman during the daytime is due to the RASS s being shut off during business hours to prevent disruption to the nearby businesses. The maximum data completeness at some sites, such as Irvine, was only about 70% to 80% because of downtimes. Given the downtimes due to instrument failures, the data completeness was good at all sites. In general, data completeness was highest at the lowest altitudes, as is expected because the radar signal returns tend to diminish as the distance from the RWP increases. In addition, the sound generated by the RASS diminishes quickly with height. At LAX, Ontario, and Moreno Valley, the data completeness at altitudes above about 600 m agl was lower during the afternoon hours than during the morning and nighttime hours. This may be due to the stronger winds typically observed during the afternoon hours. Stronger winds tend to blow the sound waves out of range more quickly, resulting in less signal detection. 2-19

34 Data Summary a) Whiteman b) Irvine Height (100 m agl) Height (100 m agl) Hour (PST) Hour (PST) c) LAX d) Ontario Height (100 m agl) Height (100 m agl) Hour (PST) e) Moreno Valley Hour (PST) 35 Height (100 m agl) Hour (PST) Figure RWP wind data completeness (%) for the period from January 1, 2008, through December 31, 2010, for (a) Whiteman, (b) Irvine, (c) LAX, (d) Ontario, and (e) Moreno Valley. Note that the RWP wind data completeness for Whiteman was calculated for the period from April 17, 2008, through December 31,

35 Data Summary a) Whiteman b) Irvine Height (100 m agl) Hour (PST) Height (100 m agl) Hour (PST) c) LAX d) Ontario Height (100 m agl) Height (100 m agl) Hour (PST) e) Moreno Valley Hour (PST) Height (100 m agl) Hour (PST) Figure RASS T v data completeness (%) for the period from January 1, 2008, through December 31, 2010, for (a) Whiteman, (b) Irvine, (c) LAX, (d) Ontario, and (e) Moreno Valley. Note that the RASS T v data completeness for Whiteman was calculated for the period from April 17, 2008, through December 31,

36 Data Summary Figure 2-24 shows the minisodar wind data completeness by height and by time of day. Note that the low data completeness for LAX at 5:45 and 17:45 PST and for Whiteman at 23:15, 23:30, and 23:45 PST are consistent with data missing in the original data files. These missing times at LAX are due to the older LAX processor s programming to reboot at 0600 and 1800 PST each day. The cause of the data gaps at Whiteman cannot be determined because of recent upgrades of the minisodar computer. However, data obtained from the minisodars since the upgrades at both sites are complete for all 15-minute averages. In general, data completeness was highest at the lowest altitudes, as is expected because the minisodar signal returns diminish as the distance from the minisodar increases. In general, the data completeness at altitudes above about 60 m agl was lowest during the nighttime and early morning hours and highest during the late morning and afternoon hours. As the atmosphere stabilizes, typically during the overnight and early morning hours, the strong wind shear gradients tend to diminish, reducing the returns from the minisodar. In addition, background noise levels may be higher at night because the temperature inversions that set up can increase the background noise levels, which can overwhelm the minisodar s ability to detect the weaker signals from higher altitude reflections. a) Whiteman Height (m agl) Time (PST) b) Irvine Height (m agl) Time (PST) c) 200 LAX d) 200 Ontario Height (m agl) Height (m agl) Time (PST) Time (PST) Figure MiniSODAR wind data completeness (%) for the period from January 1, 2008, through December 31, 2010, for (a) Whiteman, (b) Irvine, (c) LAX, and (d) Ontario. Note that the minisodar wind data completeness for Whiteman and Irvine was calculated for the period from April 17, 2008, through December 31, 2010, and May 17, 2010, through December 31, 2010, respectively. 2-22

37 Data Summary Data Recovery Figure 2-25 shows the RWP wind data recovery by height by time of day. Recall that the low mode and high modes were merged at 800 m agl. Also recall that data recovery is a measure of the number of data points received versus the number possible and does not include instrument downtimes. In general, data recovery was good, with the highest percentages at the lowest altitudes, exceeding 90% in the lowest 1000 to 1500 m agl. This trend is expected because the radar signal returns diminish as the distance from the RWP increases. In general, the data recovery at altitudes above about 1000 to 1500 m agl was lower during the morning hours than during the afternoon hours. This may be due to the generally drier air found above the temperature inversions that typically set up each morning. Recall that dry air has weaker humidity gradients, hence less effective reflectivity targets and less chance of a return signal making it back to the RWP. Figure 2-26 shows the RWP RASS T v data recovery by height and by time of day. Recall that data recovery is a measure of the number of data points received versus the number possible and does not include instrument downtimes. In general, data recovery was good with the highest percentages at the lowest altitudes, exceeding 90% in the lowest 600 m, as is expected because the radar signal returns tend to diminish as the distance from the RWP increases. In addition, the sound generated by the RASS diminishes with height. At LAX, Ontario, and Moreno Valley, the data recovery at altitudes above about 600 m agl was lower during the afternoon hours than during the morning and nighttime hours. This may be due to the stronger winds typically observed during the afternoon hours. Stronger winds tend to blow the sound waves out of range more quickly, resulting in less signal detection. 2-23

38 Data Summary a) Whiteman b) Irvine Height (100 m agl) Height (100 m agl) Hour (PST) Hour (PST) c) LAX d) Ontario Height (100 m agl) Height (100 m agl) e) Hour (PST) Moreno Valley Hour (PST) 35 Height (100 m agl) Hour (PST) Figure RWP wind data recovery (%) for the period from January 1, 2008, through December 31, 2010, for (a) Whiteman, (b) Irvine, (c) LAX, (d) Ontario, and (e) Moreno Valley. Note that the RWP wind data recovery for Whiteman was calculated for the period from April 17, 2008, through December 31,

39 Data Summary a) 14 Whiteman b) Irvine 16 Height (100 m agl) Hour (PST) Height (100 m agl) Hour (PST) c) 16 LAX d) Ontario Height (100 m agl) Height (100 m agl) Hour (PST) Hour (PST) e) 16 Moreno Valley Height (100 m agl) Hour (PST) Figure RASS T v data recovery (%) for the period from January 1, 2008, through December 31, 2010, for (a) Whiteman, (b) Irvine, (d) Ontario, and (e) Moreno Valley. Note that the RASS T v data recovery for Whiteman was calculated for the period from April 17, 2008, through December 31,

40 Data Summary Figure 2-27 shows the minisodar wind data recovery by height and by time of day. Note that the high data recovery for LAX at 5:45 and 17:45 PST and for Whiteman at 23:15, 23:30, and 23:45 PST is consistent with the data gaps identified in the data completeness statistics. Because the data recovery calculation excludes downtimes, a small number of data points can yield a high data recovery measurement. In general, data recovery was highest at the lowest altitudes, generally exceeding 90% in the lowest 60 m, as is expected because the minisodar signal returns diminish as the distance from the minisodar increases. In general, the data recovery at altitudes above about 60 m agl was lowest during the nighttime and early morning hours and highest during the late morning and afternoon hours. a) Whiteman 200 b) Irvine Height (m agl) Height (m agl) Time (PST) Time (PST) c) 200 LAX d) 200 Ontario Height (m agl) Height (m agl) Time (PST) Time (PST) Figure MiniSODAR wind data recovery (%) for the period from January 1, 2008, through December 31, 2010, for (a) Whiteman, (b) Irvine, (c) LAX, and (d) Ontario. Note that the minisodar wind data recovery was calculated for the period from April 17, 2008, through December 31, 2010, for Whiteman and for the period from May 17, 2010, through December 31, 2010, for Irvine. 2-26

41 Conclusions and Recommendations 3. Conclusions and Recommendations The purpose of this report was to summarize the operations of SCAQMD s RWP, RASS, minisodar, and surface meteorological stations at the five upper-air stations in the Los Angeles basin. In addition, a few examples of diurnal averages and wind rose calculations were presented to show the usefulness of the upper-air data to data analysts. In general, data collected from the SCAQMD PAMS network show that the major wind flows in and out of the Los Angeles Basin are being captured with the five upper-air stations. In addition, despite several downtimes due primarily to hardware failures, the five upper-air stations are operational at this time and are collecting good data. We recommend the following steps to help improve the quality of the data collected from the upper-air stations: Routine back-ups for all instruments. Currently, data collected from the RWPs with RASS and minisodars are automatically backed up each day on either a portable hard drive or a flash drive. Back-ups for the remaining instruments, listed in Table 1-3, will minimize data loss. Routine calibrations of the surface meteorological stations. While the data completeness is high, it is important to perform routine calibration checks to make sure the instruments continue to meet EPA requirements. Quality control of the data set. While the data quality is, in general, good, there are known problems that can affect upper-air data in particular. For example, during periods of convective rainfall, the RWP may be unable to detect the actual winds, instead reporting false high winds. While automatic quality control routines are being used, they do not catch all potential problems. In addition, to further utilize the data collected from the upper-air stations, we recommend: Creation of routine displays of moments and mixing height data derived from the RWP. The mixing heights can be used to assist in the forecasting of ozone concentrations throughout the Los Angeles Basin. In addition, the mixing heights can be used to refine air quality models. Comparison of meteorological data collected from the upper-air stations with pollution data from nearby monitoring sites. The meteorological data can be compared to nearby pollution data to help explain why peak concentrations of pollutants occur in different portions of the Los Angeles Basin. 3-1

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43 References 4. References U.S. Environmental Protection Agency (2000) Meteorological monitoring guidance for regulatory modeling applications. Office of Air Quality Planning and Standards, Research Triangle Park, NC, Document EPA-454/R , February. Available on the Internet at U.S. Environmental Protection Agency (2008) Quality assurance handbook for air pollution measurement systems Volume IV: meteorological measurements version 2.0 (final). Prepared by the U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Air Quality Assessment Division, Research Triangle Park, NC, EPA- 454/B , March. Available on the Internet at ments.pdf. 4-1

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45 Appendix A Appendix A Diurnal Wind Averages A-1

46 Appendix A The incorrect starting dates that appear within the following figures are automatically generated by the LAPDat software for the complete data set being used and do not reflect the date range of the data used to generate the figure. The date in the figures upper right corner is correct. RWP Diurnal Averages e) Figure A-1. RWP diurnal wind averages for a) Whiteman, b) Irvine, c) LAX, d) Ontario, and e) Moreno Valley for the period from January 1, 2008, to December 31, 2008, in 200 m height bins. A-2

47 Appendix A e) Figure A-2. RWP diurnal wind averages for a) Whiteman, b) Irvine, c) LAX, d) Ontario, and e) Moreno Valley for the period from January 1, 2009, to December 31, 2009, in 200 m height bins. A-3

48 Appendix A e) Figure A-3. RWP diurnal wind averages for a) Whiteman, b) Irvine, c) LAX, d) Ontario, and e) Moreno Valley for the period from January 1, 2010, to December 31, 2010, in 200 m height bins. A-4

49 Appendix A e) Figure A-4. RWP temperature profile for a) Whiteman, b) Irvine, c) LAX, d) Ontario, and e) Moreno Valley for the period from January 1, 2008, to December 31, 2008, in 200 m height bins. A-5

50 Appendix A e) Figure A-5. RWP temperature profile for a) Whiteman, b) Irvine, c) LAX, d) Ontario, and e) Moreno Valley for the period from January 1, 2009, to December 31, 2009, in 200 m height bins. A-6

51 Appendix A e) Figure A-6. RWP temperature profile for a) Whiteman, b) Irvine, c) LAX, d) Ontario, and e) Moreno Valley for the period from January 1, 2010, to December 31, 2010, in 200 m height bins. A-7