Publications

Nandy, S; Saranya, M; Srinet, R (2022). Spatio-temporal variability of water use efficiency and its drivers in major forest formations in India. REMOTE SENSING OF ENVIRONMENT, 269, 112791.

Abstract
Forests play a significant role in mitigating the effects of climate change and regulating the biogeochemical cycles. Water use efficiency (WUE) is an important indicator that links the carbon and water cycles in terrestrial ecosystems. In the present study, WUE of major forest formations of India was calculated from 2003 to 2018 as the ratio of Moderate Resolution Spectroradiometer (MODIS) Gross Primary Productivity (GPP, MOD17A2H) to evapotranspiration (ET, MOD16A) using the Google Earth Engine platform. The spatial distribution of WUE was mapped and the inter-annual and monthly variations were analysed. The mean annual WUE of forests ranged from 1.78-2.02 gC kgH2O-1. It was observed that tropical thorn forests had the highest WUE (3.52 +/- 1.08 gC kgH2O-1) and moist alpine scrub had the lowest WUE (1.05 +/- 0.17gC kgH2O-1) among the forest type groups of India. WUE of forests showed an increasing trend with latitude and decreasing trend with elevation. To understand the influence of various bio-meteorological drivers on WUE and their importance in governing these influences, Random Forest (RF) algorithm was used. The bio-meteorological drivers were able to explain 65% of the variability in WUE. Temperature was identified as the most important driver in influencing the WUE of forests. Based on the findings of the study, it can be expected that the global increase in temperature would negatively affect the WUE of the major forest formations of India.

DOI:
10.1016/j.rse.2021.112791

ISSN:
1879-0704