Spatial Variability of Aerosol - Cloud Interactions over Indo - Gangetic Basin (IGB)

Transcription

1 Spatial Variability of Aerosol - Cloud Interactions over Indo - Gangetic Basin (IGB) Shani Tiwari Graduate School of Environmental Studies Nagoya University, Nagoya, Japan pshanitiwari@gmail.com tiwari.shani@i.mbox.nagoya-u.ac.jp

2 Thanks to... Prof. S. Ramachandran (Physical Research Laboratory, Ahmedabad) Prof. Abhay Kumar Singh (Banaras Hindu University, India) Prof. T. Shibata, Nagoya University, Japan Dr. S. Singh (National Physical Laboratory, New Delhi, India) Dr. Atul Srivastava, (IITM, Pune, India) NASA team for Satellite data (MODIS, TRMM). ACAM and Jinan University China for financial supports.

3 Aerosol Impacts on Earth system and Human Being Socio-economic system and human well being Climate Impacts???? Aerosol Atmospheric Composition and Chemistry Biogeochemical cycles Ecosystem functioning

4 Climate Impact of Atmospheric Aerosol 1. Direct Effect : Absorption (dust) and scattering (sulphates) of solar radiation by aerosols. 2. Indirect Effect: Effects of aerosol on cloud properties. 3. Semi Direct Effect: Evaporation of the cloud, cloud burn off. Aerosol Cloud & Precip. Climate

5 Global Radiative Forcing Well understood and quantified Cloud radiative forcing shows strong cooling effect at top of the atmosphere Spatial-temporal variation Inadequate knowledge about aerosol-cloud interaction (Model Sensitivity) Low understanding Addresses IPCC, 2013 Observations & Numerical Modeling Tools

6 Instruments used for the present study Moderate Resolution Imaging Spectro-radiometer (MODIS) : 36 Spectral band from 0.4 µm to 14.4 µm At 470, 550 and 660 nm over land and 470, 550, 660, 865, 1200, 1600 and 2100 nm over ocean. Daily level 3, version 6.0 AOD, and cloud parameters data are used Spatial resolution of 1 1 ( gov/). Tropical Rainfall Measurement Mission (TRMM) : Daily TRMM_B342_Daily_v7 rainfall data Terra Satellite Very high spatial resolution of x

7 Why Indo-Gangetic Basin? Srivastava et al.,

8 Heterogeneity in aerosol types and annual their contributions Tiwari et. al, Environ Sci Pollut Res (2015) 22:

9 Methodology R 2 R 3 R 1 R 4 R5 R 6 Divided whole IGB in equal six sub regions (5 0 x 5 0 ) JJAS Normal Years: 2000, 01, 03, 05, 06, 07, 10, 11, 12 and 13. JJAS Drought Years : 2002, 04, 09, 14 and 15.

10 Preliminary Results and Discussion

11 Linear regression analysis of cloud parameters as a function of AOD during Normal Years S = 9.48, I = R = 0.95 S = -0.07, I = R = 0.12 S = -1.08, I = R = 0.21 S = 0.46, I = R = 0.40 R 1 S =8.82, I = 3.90 R = 0.92 S = -0.11, I = R = 0.27 S = -1.31, I = R = 0.39 S = 0.27, I = 1.34 R = 0.29 R 2 S =10.19, I = R = 0.95 S = -0.02, I = R = 0.03 S = -1.64, I = R = 0.44 S = 0.44 I = 1.03 R =0.38 R 3 S =10.64, I = R = 0.96 R = 0.02 S = 0.002, I = S = -1.52, I = R = 0.37 S = 0.40 I = 2.88 R =0.32 R 4 S = I = R = 0.96 R = 0.09 S = , I = S = -1.52, I = R = 0.38 S = 0.56 I = 3.54 R =0.36 R 5 S = 11.22, I = R = 0.94 R = 0.16 S = -0.06, I = S = -1.20, I = R = 0.38 S = 0.30 I = 7.36 R =0.21 R 6 Cloud Optical Depth (COD)

12 Linear regression analysis of cloud parameters as a function of AOD during Drought Years S = 8.78, I = 5.98 R = 0.94 S = -0.17, I = R = 0.28 S = -0.30, I = R = 0.06 S = 0.37, I = R = 0.40 R 1 S = 8.49, I = 2.94 R = 0.92 S = -0.06, I = R = 0.18 S = -1.78, I = R = 0.39 S = 0.26, I = 0.45 R = 0.31 R 2 S = 9.99, I = 5.01 R = 0.96 S = -0.02, I = R = 0.04 S = -1.27, I = R = 0.42 S = 0.45, I = R = 0.46 R 3 S = 9.98, I = R = 0.96 S = -0.03, I = R = 0.06 S = -1.18, I = R = 0.28 S = 0.29 I = 3.15 R = 0.24 R 4 S = I = R = 0.95 R = 0.07 S = -0.03, I = S = -1.65, I = R = 0.39 S = 0.47 I = 4.27 R = 0.31 R 5 S = 10.97, I = 1.31 R = 0.93 R = 0.17 S = -0.07, I = S = -1.21, I = R = 0.36 S = 0.30 I = 6.81 R = 0.21 R 6 Cloud Optical Depth (COD)

13 Frequency Distribution of AOD and Cloud Fraction R 1 R 2 R 3 R 4 R 5 R 6

14 Frequency Distribution of Cloud Properties During drought years, CER R 1 decreases for value greater than 20 µm (i.e. CER > 20 µm) over R1 to R4 while R5 and R6 have nearly similar value. R 2 Liquid water path have maximum R 3 contribution in the range of gm-2 except R1 and R6 for both Normal and Drought Years. R 4 Over R1, LWP decrease for bin gm-2 while it increases for R3 which may be mainly due to different emission aerosol source. R 5 R 6

15 Summary A negative gradient in aerosol loading is observed from western to eastern IGB. A slightly increment in AOD can affect the significant contribution cloud fraction over the region which also show the spatial heterogeneity. A strong correlation between cloud optical depth and liquid water path is obtained. CER (>20 um) decreases from R1 to R4 suggesting the enhancement in cloud albedo. A significant spatial variability in aerosol cloud interaction is observed over IGB. A further study is needed to understand the influence of aerosol cloud interaction over IGB on Indian Summer Monsoon.

16 Thank You!! Suggestions are welcome

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18 R 1 Liquid Phase Cloud Ice Phase Cloud R 3 Liquid Phase Cloud Ice Phase Cloud

19 Linear regression analysis of cloud parameters as a function of AOD during Normal Years (for Ice Phase Cloud) Cloud Optical Depth (COD)

20 Linear regression analysis of cloud parameters as a function of AOD during Drought Years (for Ice Phase Cloud) Cloud Optical Depth (COD)

21 Frequency Distribution of Ice Phase Cloud Properties

22 Heterogeneity in aerosol types and annual their contributions Tiwari et. al, Environ Sci Pollut Res (2016) 23:

23 What are Aerosols.??

24 Dust storm Industrial emission sea-salt Urbanization Volcanic eruption Biomass Burning Transportation

25 Indirect Effect

26 Climate Impact of Atmospheric Aerosol Sun Direct Effect Sun Absorbing aerosols Scattering aerosols Solar radiation absorbed (Warming) e.g. Black carbon, mineral dust Solar radiation scattered to space (Cooling) e.g. Sulphates, nitrates, organics Most aerosols both absorb and scatter!

27 Semi-direct Effect Aerosols absorb solar radiation Evaporation of the cloud! Absorbing aerosols may reduce low cloud cover Warm the troposphere. Absorbing aerosols in and around a cloud Cloud burn-off