Applications of satellite measurements on dust-cloud-precipitation interactions over Asia arid/semi-arid region Jianping Huang Key Laboratory for Semi-Arid Climate Change College of Atmospheric Sciences Lanzhou University, Lanzhou, China Contributors: P. Minnis, B. Chen, J. Su, J. Ge, H. Yan, W. Wang, T. Wang, S. Chen, Q. Fu 2012 AMS Meeting
Northwest China is arid/semi-arid area
This area is the a major source region of dust storm Distribution of Dust Storm over China
Heavy Dust Storms (April 24, 2010) Instantly wind up to 28m/s, Visibility 0 m
Instantly wind up to 28m/s, Visibility 0 m April, 24 th 2010
Dust experiment Two sites for Dust Experiment, 2010 Minqin 民勤 SACOL
The Lidar results in Minqin Heavy Dust Storms (April 24, 2010) Heavy Dust Storms (April 24, 2010) Minqing Dust aerosols Dust aerosols
The Lidar results in SACOL Dust aerosols Dust aerosols
Backward Trajectories for the dusty case The dust aerosols transport from Minqin to SACOL. MinQin SACOL
Weather situation strong convergence and downdraft western UTC 0 on April 24th
Long-range dust aerosol transport Nobuo Sugimoto,Atsushi Shimizu 提供 Nobuo Sugimoto,Atsushi Shimizu 提供 Huang et al., JGR, 2008 Nobuo Sugimoto,Atsushi Shimizu 提供
The VFM and transmission of the dusty case Dust aerosols Dusty cloud Dusty cloud Dust aerosol Dusty original cloud from Northwest China can flow out from the continent to the open sea, may has some impact on cloud, regional & global climate. It is important to study the dust aerosols effect on cloud and climate in different region. 0=invalid (bad or missing data),1=clear air, 2=cloud, 3=aerosol, 4=stratmospheric, 5=surface, 6=subsurface, 7=no signal
Aerosols Direct Effect Semi-Direct Effect Indirect Effect Diffusion Absorption & Scattering Cloud Formation Plant Production & Carbon Sink Atmospheric Radiation Budget Precipitation & Land Process Carbon Cycle Energy Cycle Water Cycle Aerosols Effect on Climate
The direct dust aerosol effect Absorb solar radiation! Heating Atmosphere!
Huang et al., ACP, 2010 CALIPSO 532nm backscattering intensity over Taklamkan Desert for: July24, 26, 29, 30, 31, 2006.
Aerosol Index derived from AURA There is dust storm over Taklimakan from July 25 Aug.1, 2006
Single Scattering Albedo Asian Dusts are more absorbing Ge et al., JGRL, 2010 Comparison of Asian Dust Single Scattering Albedo versus Saharan and Saudi Arabian Dust 1.00 0.98 0.96 0.94 0.92 0.90 Beijing Anmyon, S. Korea Dunhuang, China Kanpur, India Cape Verde Saudi Arabia - SV Bahrain 0.88 400 500 600 700 800 900 1000 1100 Wavelength (nm) T. Eck et al 2004 Retrieved singlescattering albedo
Asia dust may heat atmosphere over source region much stronger than we know before Huang et al., ACP, 2009
Indirect aerosol effect Higher droplet Concentration (CCN) Smaller droplets Lower Precipitation rate Clouds longer lived More reflective cloud (Cooler climate)
Case Study: March 27, 2004 CLD DUST COD PCOD
Satellite Data Analysis: Indirect Effect of Dust Aerosol Reduce the ice diameter and increase high cloud cover Huang et al., GRL, 2006a Comparison of ice cloud diameter over the dust-free cloud (CLD) and clouds over the dust (COD) region. Correlation between Taklamagan dust storm index and ISCCP high cloud amount.
Dust indirect effect was evidenced by observation Huang et al., GRL, 2006a Dust Aerosol, as Cloud condensation nuclei (CCN), can change cloud microphysical property, cloud fraction and cloud lifetime, thus can indirectly influence the radiation budget of the earth-atmosphere system.
The semi-direct aerosol effect Absorb solar radiation Evaporation of the cloud! Reduce low cloud cover Evaporation Warm the climate as low clouds scatter solar radiation back to space.
Semi-Direct Effect of Dust Aerosol Reduce low cloud water Path Huang et al., GRL, 2006b Comparison of low cloud water path over the dust-free cloud (CLD) and clouds over the dust (COD) region.
Semi-Direct Effect of Dust Aerosol Reduce low cloud water Path Huang et al., GRL, 2006b Comparison of the cloud water path for dust-free with cloud over dust region as a function of effective cloud top temperature Te for (a) IWP, (b) LWP.
Semi-Direct Effect of Dust Aerosol Reduce low cloud water Path Huang et al., GRL, 2006b Correlation between dust storm index & ISCCP cloud optical depth. Correlation between dust storm index and ISCCP low cloud total water path
Semi-direct effect may contribute to arid climate a evaporation disappearance Huang et al., GRL, 2006b Dust Aerosols semi-direct effect can increase droplet evaporation, reduce liquid water path by 49.8%, lead to less precipitation.
81% dusty cloud warming effect is contributed by indirect/semi-direct effect, 19% from direct effect Su & Huang et al, ACP, 2008
CRF Dusty cloud reduced net TOA cloud cooling effect by 40% and may lead to warm atmosphere. -300-250 NET RF (COD) NET RF (CLD) -200-150 Su & Huang et al, ACP, 2008-100 -50 0 2003 2004 Year 2005 2006 Comparison of the annual mean net radiative forcing at the TOA.
Frequency(%) Frequency(%) Frequency(%) Frequency(%) Dust aerosol reduce cloud particle size in both source & downwind region but much significant in source region 100 100 80 Pure Cloud(11.65) Dusty Cloud(9.3) 80 Pure Cloud(11.88) Dusty Cloud(11.68) 60 60 40 40 20 20 Source Region 0 2 6 10 14 18 22 26 30 34 38 Re of Water Cloud in Source Region(um) 0 2 6 10 14 18 22 26 30 34 38 Re of Water Cloud in Downwind Region(um) Downwind Region 100 100 80 Pure Cloud(43.99) Dusty Cloud(35.69) 80 Pure Cloud(55.28) Dusty Cloud(51.65) 60 60 40 40 20 20 0 10 30 50 70 90 110 130 De of Ice Cloud in Source Region(um) 0 10 30 50 70 90 110 130 De of Ice Cloud in Downwind Region(um) Wang & Huang et al., JGR, 2010
Dusty cloud reduce net TOA cloud cooling effect in both source & downwind region but much significant in source region D Dusty P Pure W Water I Ice Wang & Huang et al., JGR, 2010
Global precipitation distribution. The black rectangles denote the semi-arid regions over China (CSR) and over the USA (USR)
Huang et al., ACP, 2010 Comparison of vertical structure of dust aerosol occurrence from CALIPSO over (a) China Semi-arid Region (CSR) and (b) US Semi-Arid Region (USR)
Huang et al., ACP, 2010 DED: Dust event day NDE:No dust event day Comparison of aerosol optical depth (left) and absorbing aerosol index (right ) over China Semi-arid Region (CSR) and US Semi-Arid Region (USR)
Huang et al., ACP, 2010 DED: Dust event day NDE:No dust event day Comparison of cloud properties over China Semi-arid Region (CSR) and US Semi-Arid Region (USR)
Dust aerosols effect on cloud Indirect effect dust dust transport Change the microphysical characteristics of clouds & diminish the cloud cooling effect Heating atmosphere dust Direct effect Low-level cloud evaporation, water vapor reduction Semi-direct effect
Summery and Discussion Less Rainfall Drought Dust Events More Dust Events Huang et al., ACP 2010 Wang et al., JGR 2010 Huang et al., ACP 2009 Huang et al., JGR 2008 Su et al., ACP 2008 Huang et al., GRL 2006a,b Dust-Drought Feedback Evaporate cloud droplets Reduce cloud water path Less Rainfall Drought
Summery and Discussion: The absorption of Asian dust aerosol can cause: heating atmosphere evaporate cloud droplets reduce cloud water path and optical depth reduce cloud-cooling effect lead to warm local climate lower precipitation rate More field cloud/aerosol observation need to understand the their effect on climate and hydrological cycle.
Thank you for your attention!