BSRN Station Sonnblick

Transcription

1 Spawning the Atmosphere Measurements, Jan 2014, Bern BSRN Station Sonnblick Baseline surface radiation network station Sonnblick Marc Olefs, Wolfgang Schöner ZAMG Central Institute for Meteorology and Geodynamics, Vienna, Austria.

2 Spawning the Atmosphere Measurements 2014 Bern What s the motivation for radiation monitoring at Sonnblick? Radiation concerns everybody! (directly or indirectly) Sun = Main driver for changes in the earth s climate Basic research (climate): high quality, longterm measurements needed for trend analysis and to improve process understanding (e.g. why does the air temperature show a decreasing trend or in general anthropogenic influences vs. natural changes, ) Applied research: Validation/calibration of models and satellite data (Meteorological for- and nowcasting models, (regional) climate models, energy balance (e.g. snow cover), micro-meteorology, dispersion modeling, solar energy, ) Legal task national weather service (ZAMG): Constant monitoring of climate and its changes using state-of-the-art methods

3 C Abweichungen vom Mittel des 20.Jahrhunderts Spawning the Atmosphere Measurements 2014 Bern solar + Vulkanismus 3 GHGs Temperature anomaly NH since 1850: Main drivers: changes in short- & longwave radiation Sulfat Time-series of measured global radiation Station Wien Hohe Warte Dimming Brightening Monitoring changes in radiation is very important for climate monitoring as radiation is very high up in the process chain!

4 Spawning the Atmosphere Measurements 2014 Bern Where is the Sonnblick Observatory? Summit of Hoher Sonnblick at 47 03'14.9''N ; 12 57'27.2''E and 3106 m a.s.l. Austrian province of Salzburg Alpine main ridge DEM BEV 2012 Photo: G. Weyss

5 Spawning the Atmosphere Measurements 2014 Bern Suntracker 2 AP operational since Jan 2011 (ZAMG): Global, diffuse and direct radiation, longwave incoming (2 x CMP21, 1 x CHP 1, 1 x CGR 4), Heating/Ventilation device PMOD Davos until April 2012, Eigenbrodt since then, Heating Power: 25 W Local horizon S N

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7 Measurement principle & technical aspects K&Z CMP Manual CMP21 CGR4 CHP1 Pyranometer (shortwave global and diffuse radiation): Radiation from the upper hemisphere heats a black coated receiver surface (thermopile) beneath a glas dome voltage output proportional to radiation intensity (around 8-14 μv/wm -2 ) Active measurement device Glas dome defines spectral range (& reduces zero-offset ) Sensitivity of thermopile unique -> Each sensor needs calibration factor Important: low temperature gradient between instrument body and dome Heating/Ventilation device reduces: Temp. gradient, solid and liquid deposition on sensor surface

8 Integration in national / international networks: National: Austrian radiation measurement network (ARAD) Cooperation with Universities (Innsbruck, Graz, Vienna) 5 Stations: Wien (198 m a.s.l.) Graz (400 m a.s.l.) Innsbruck (580 m a.s.l.) Kanzelhöhe (candidate, 1520 m a.s.l.) Sonnblick (3109 m a.s.l.) Methods and standards following BSRN criteria Data since summer 2011 (GLO, DIFF, DIR, LWIN)

9 Integration in national / international networks: Baseline surface radiation network (BSRN): GEWEX/WCRP project with currently 57 worldwide stations Aim: To detect important changes in surface radiation budget Data of primary importance for satellite and computer model estimates

10 BSRN requirements and data quality assurance procedure at Sonnblick BSRN = state of the art +, consistently highest worldwide measurements standards for radiation monitoring (sensors, calibration, data acquisition system, maintenance, quality control) Daily maintenance (2 observers, 24 h on duty) following BSRN guidelines (cleaning, leveling, ventilation, de-riming, ), daily report via web External maintenance if required (mechanics, calibration, special problems) Daily automatic control algorithms/report and manual data quality control and flag setting in database. >50 criteria (Long and Shi, 2008 ; own criterias) Hourly automatic check of most critical parameters, in case of fail -> ALARM via Realtime data visualization tool

11 Interactive realtime graphs (amcharts.com) Daily report

12 What about the quality of the radiation data at Sonnblick? Flag-Statistik GLO (Relativ %) Flag Wien Graz Innsbruck Sonnblick Korrekt (1) Falsch (2) Zweifelhaft (3) Fehlwerte (255) Summe Flag-Statistik LWO (Relativ %) Flag Wien Graz Innsbruck Sonnblick Korrekt (1) Falsch (2) Zweifelhaft (3) Fehlwerte (255) Summe Flag Statistik GLO&HIM&DIR&LWO (Relativ %) Flag Wien Graz Innsbruck Sonnblick Korrekt (1) Falsch (2) Zweifelhaft (3) Fehlwerte (255) Yield of good data: 60 % Sonnblick, (>90% lower stations)

13 Whats is the main problem for the data quality at Sonnblick? Hoarfrost!

14 Special modifications Sonnblick Icing/Rime Original inlet of heating/ventilation unit (grid) beneath the sensor platform Lead to reduced airflow and thus to ice formation around glas domes Measurment errors Difference GLO vs. Diff. SOLUTION!

15 diffuse rad. (rel. Intensity) Motivation Radiation Sonnblick Measured radiation data Sunshine duration: 1887-present Cloudiness: 1887-present Global radiation: 1957-present Diffuse radiation: 1970-present UV & total ozon: 1994-present Suntracker: since min. vals since 1970 Global radiation in Austria Annual sums Seasonal sums Olefs and Schöner, 2011 Weak vertical gradients In summertime (convective cloudiness) Dirmhirn, 1951 Cloudiness

16 Wien Hohe Warte (198 m a.s.l.) GLO HIM DIR_hori LWO Sonnblick (3105 m a.s.l.) Absolute Minima and Maxima are given for 1 minute means

17 SLR Webcam Sonnblick (

18 Temporal changes of radiation climate et Sonnblick Sunshine duration & global radiation: decrease after : increase 2007-today: decreasing tendency Sunshine duration and global radiation do not have always the same course. Especially not at Sonnblick! Why?

19 A typical aspect of the radiation climate at Sonnblick: high temporal variability and frequent Multiple/terrain reflections (GLO or DIFF values > top of the atmosphere solar radiation). -> GLO values can be very high without direct sunshine!

20 Data use / Dissemination of radiation data at Sonnblick Freely available for scientific community in general: Upload to BSRN data archive in monthly packages since Jan ECMWF: improvement of NWP models: operational validation of radiation fluxes (T.Haiden) ZAMG: data quality cross check for other meteorological variables (e.g. sunshine duration) ZAMG: calibration and validation of solar radiation, energy balance-, for- and nowcasting models ZAMG & universities: academic and scientific work with the data (teaching, thesis, ) ZAMG: Legal task of state of the art climate monitoring (as national weather service) ARAD Paper planned for 2014

21 Data use / Dissemination of radiation data at Sonnblick (EXAMPLES) Calibration and validation of the operational solar radiation model STRAHLGRID at ZAMG Calibration of MSG-2 cloudtypes against measured DIFF data for parameterization of cloudiness Effects in the model

22 Data use / Dissemination of radiation data at Sonnblick (EXAMPLES) Calibration and validation of the energy fluxes operational snow cover model SNOWGRID at ZAMG (in development) Longwave incoming radiation Calculated and observed snow extent

23 Data use / Dissemination of radiation data at Sonnblick (EXAMPLES) improvement of NWP models: operational validation of radiation fluxes (T.Haiden) Verification of ECMWF short-range (+24 h) forecasts of daily averages of the downward solar (top) and longwave (bottom) flux at the surface. Monthly values of mean error (bias) shown in blue, error standard deviation in red. Dashed curves show corrected bias (gradient of -3 W/m² per 100 m (Marty et al. 2002)). (Courtesy of Thomas Haiden, ECMWF)

24 TAKE HOME POINTS 1 In order to best understand the climate system and its processes it is key to monitor solar and longwave radiation as long and as acccurate as possible. 2 A high effort is needed in order to aquire high quality radiation data at such an extreme site 3 Selected sites as the Sonnblick with a special (radiation) climate are essential to properly calibrate and validate models and satellite data as high altitude measurements are rare. 4 High quality radiation data from Sonnblick is used for a waste variety of applications, from fundamental climate research to applied problems.

25 Thank you very much for your attention! Questions?