Development of a Regression Model for Estimating Daily Radiative Forcing Due to Atmospheric Aerosols from Moderate Resolution Imaging Spectrometers (MODIS) Data in the Indo Gangetic Plain (IGP)

Shreemat Shrestha,Graham Moore,Murray Peel

doi:10.3390/atmos9100405

Abstract

The assessment of direct radiative forcing due to atmospheric aerosols (ADRF) in the Indo Gangetic Plain (IGP), which is a food basket of south Asia, is important for measuring the effect of atmospheric aerosols on the terrestrial ecosystem and for assessing the effect of aerosols on crop production in the region. Existing comprehensive analytical models to estimate ADRF require a large number of input parameters and high processing time. In this context, here, we develop a simple model to estimate daily ADRF at any location on the surface of the IGP through multiple regressions of AErosol RObotic NETwork (AERONET) aerosol optical depth (AOD) and atmospheric water vapour using data from 2002 to 2015 at 10 stations in the IGP. The goodness of fit of the model is indicated by an adjusted R2 value of 0.834. The Jackknife method of deleting one group (station data) was employed to cross validate and study the stability of the regression model. It was found to be robust with an adjusted R2 fluctuating between 0.813 and 0.842. In order to use the year-round ADRF model for locations beyond the AERONET stations in the IGP, AOD, and atmospheric water vapour products from MODIS Aqua and Terra were compared against AERONET station data and they were found to be similar. Using MODIS Aqua and Terra products as input, the year-round ADRF regression was evaluated at the IGP AERONET stations and found to perform well with Pearson correlation coefficients of 0.66 and 0.65, respectively. Using ADRF regression model with MODIS inputs allows for the estimation of ADRF across the IGP for assessing the aerosol impact on ecosystem and crop production.

Highlights

The Indo Gangetic Plain (IGP) is considered to be one of the most highly polluted regions of the world due to persistent heavy aerosol loading in its atmosphere [1,2]
In the first sub-section, the year round and seasonal ADRF models that were developed through multiple regression using AErosol RObotic NETwork (AERONET) data at 10 stations in the IGP region are presented
To use the developed year-round ADRF model beyond the AERONET stations in the IGP, two model input parameters aerosol optical depth (AOD) and precipitable water vapour retrieved from Moderate Resolution Imaging Spectrometers (MODIS) Aqua and Terra are compared against AERONET values in the third sub-section

Summary

Introduction

The Indo Gangetic Plain (IGP) is considered to be one of the most highly polluted regions of the world due to persistent heavy aerosol loading in its atmosphere [1,2]. Due to the high level of air pollution, premature mortality as a result of exposure to PM2.5 in the Indian section of IGP alone is estimated to be 240,000 per annum [3]. The burning of crop residue (rice and wheat) in the field has significantly contributed to the high level of aerosols during the post monsoon and pre monsoon seasons in the IGP [7,8,9,10,11].

Objectives

Methods

Results

Conclusion