Remotely sensed MODIS wetland components for assessing the variability of methane emissions in Indian tropical/subtropical wetlands.

Temperature and area fluctuations in wetlands greatly influence its various physico-chemical characteristics, nutrients dynamic, rates of biomass generation and decomposition, floral and faunal composition which in turn influence methane (CH 4 ) emission rates. In view of this, the present study attempts to up-scale point CH 4 flux from the wetlands of Uttar Pradesh (UP) by modifying two-factor empirical process based CH 4 emission model for tropical wetlands by incorporating MODIS derived wetland components viz . wetland areal extent and corresponding temperature factors (F t ). This study further focuses on the utility of remotely sensed temperature response of CH 4 emission in terms of F t . F t is generated using MODIS land surface temperature products and provides an important semi-empirical input for up-scaling CH 4 emissions in wetlands. Results reveal that annual mean F t values for UP wetlands vary from 0.69 (2010–2011) to 0.71(2011–2012). The total estimated area-wise CH 4 emissions from the wetlands of UP varies from 66.47 Gg yr −1 with wetland areal extent and F t value of 2564.04 km 2 and 0.69 respectively in 2010–2011 to 88.39 Gg yr −1 with wetland areal extent and F t value of 2720.16 km 2 and 0.71 respectively in 2011–2012. Temporal analysis of estimated CH 4 emissions showed that in monsoon season estimated CH 4 emissions are more sensitive to wetland areal extent while in summer season sensitivity of estimated CH 4 emissions is chiefly controlled by augmented methanogenic activities at high wetland surface temperatures. [ABSTRACT FROM AUTHOR]