scholarly journals Revisiting the observed correlation between weekly averaged Indian monsoon precipitation and Arabian Sea aerosol optical depth

2017 ◽  
Vol 44 (19) ◽  
Author(s):  
Disha Sharma ◽  
Ron L. Miller
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Arabian Sea ◽  
Indian Monsoon ◽  
Monsoon Precipitation ◽  
Sea Aerosol

scholarly journals Validation of MODIS derived aerosol optical depth and an investigation on aerosol transport over the South East Arabian Sea during ARMEX-II

2009 ◽  
Vol 27 (6) ◽  
pp. 2285-2296 ◽  
Author(s):  
M. Aloysius ◽  
M. Mohan ◽  
S. Suresh Babu ◽  
K. Parameswaran ◽  
K. Krishna Moorthy
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Mass Concentration ◽  
Arabian Sea ◽  
Second Phase ◽  
The South ◽  
Monsoon Period ◽  
Lower Altitude ◽  
The North ◽  
Coarse Mode

Abstract. The influence of wind and humidity on aerosol optical depth (AOD) over the Arabian sea is being investigated using MODIS (Moderate Resolution Imaging Spectroradiometer) Level 3 (Collection-5) and NCEP (National Centres for Environmental Prediction) reanalysis data for the second phase of the Arabian Sea Monsoon Experiment (ARMEX-II) over the South East Arabian Sea (SEAS) in the pre-monsoon period (14 March–10 April 2003). In order to qualify MODIS data for this study, MODIS aerosol parameters were first compared with ship borne Microtops measurements. This showed correlations 0.96–0.97 in the case of spectral AODs and a correlation 0.72 for the angstrom exponents. The daily AOD data from MODIS and winds from NCEP reveal that the ship observed episodic enhancement and decay of AOD at the TSL (Time Series Location) during 23 March–6 April 2003 was caused by the southward drift of an aerosol pocket driven by an intensification and reduction of surface pressure in the North Western Arabian Sea with a low altitude convergence prevailing over SEAS. The AOD increase coincided with a decrease in the Angstrom exponent and the fine mode fraction suggesting the pocket being dominated by coarse mode particles. A partial correlation analysis reveals that the lower altitude wind convergence is the most influential atmospheric variable in modulating AOD over the ARMEX-II domain during the TSL period. However, surface winds at a distant zone in the north/north west upwind direction also had a moderate influence, though with a lag of two days. But this effect was minor since the winds were not strong enough to produce marine aerosols matching with the high AODs over the ARMEX-II domain. These findings and the similarity between MODIS column mass concentration and the ship borne QCM (Quartz Crystal Microbalance) measured coarse mode mass concentration, suggest that the aerosol pocket was mostly composed of coarse mode mineral dust in the lower atmospheric altitudes transported from the Arabian deserts.

scholarly journals Multi year changes of Aerosol Optical Depth in the monsoon region of the Indian Ocean since 1986 as seen in the AVHRR and TOMS data

2008 ◽  
Vol 26 (1) ◽  
pp. 7-11 ◽  
Author(s):  
J. P. George ◽  
L. Harenduprakash ◽  
M. Mohan
Keyword(s):  
Indian Ocean ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Arabian Sea ◽  
Mean Value ◽  
North West ◽  
West Indian Ocean ◽  
Indian Ocean North ◽  
The Indian Ocean ◽  
Second Period

Abstract. Aerosol Optical Depth (AOD) data based on AVHRR and TOMS was analyzed to find out the changes in the Indian Ocean from 1981 to 2004. Four regions covering Indian Ocean north of 10° S were studied in detail. The results strongly suggest that the mean value of AOD in these regions decreased from 1986–1990 to 1995–1999. The Arabian Sea and Bay of Bengal show increase thereafter whereas in the equatorial part it decreased further, during 2000–2004. The drop in AOD from the first to second period is evident in AVHRR and TOMS in the case of the Arabian Sea (North West Indian Ocean). The decrease in this case is prominent in summer. These results in general agree with the recently reported global decrease in AOD, "global brightening" and also the reversal of trend in some of the anthropogenic emissions.

Aerosol optical depth, physical properties and radiative forcing over the Arabian Sea

2005 ◽  
Vol 91 (1-4) ◽  
pp. 45-62 ◽  
Author(s):  
S. K. Satheesh ◽  
K. Krishna Moorthy ◽  
Y. J. Kaufman ◽  
T. Takemura
Keyword(s):  
Physical Properties ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Arabian Sea

scholarly journals A decadal regional and global trend analysis of the aerosol optical depth using a data-assimilation grade over-water MODIS and Level 2 MISR aerosol products

2010 ◽  
Vol 10 (8) ◽  
pp. 18879-18917 ◽  
Author(s):  
J. Zhang ◽  
J. S. Reid
Keyword(s):  
Data Assimilation ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Bay Of Bengal ◽  
Arabian Sea ◽  
East Coast ◽  
Radiometric Calibration ◽  
Anthropogenic Aerosols ◽  
Global Trend ◽  
Increasing Trends

Abstract. Using the ten-year (2000–2009) DA quality Terra MODIS and MISR aerosol products, as well as 7 years of Aqua MODIS, we studied both regional and global aerosol trends over oceans. This included both natural and data assimilation grade versions of the products. Contrary to some of the previous studies that showed a decreasing trend in aerosol optical depth (AOD) over global oceans, after correcting for what appears to be aerosol signal drift from the radiometric calibration of both MODIS instruments, we found MODIS and MISR agreed on a statistically negligible global trend of 0.0003/per year. Our study also suggests that AODs over the Indian Bay of Bengal, east coast of Asia, and Arabian Sea show statistically significant increasing trends of 0.07, 0.06, and 0.06 per ten years for MODIS, respectively. Similar increasing trends were found from MISR, but with less relative magnitude. These trends reflect respective increases in the optical intensity of aerosol events in each region: anthropogenic aerosols over the east coast of China and Indian Bay of Bengal; and a stronger influence from dust events over the Arabian Sea. Negative AOD trends are found off Central America, the east coast of North America, and the west coast of Africa. However, confidence levels are low in these regions, which indicate that longer periods of observation are necessary to be conclusive.

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