Terrestrial primary productivity plays a pivotal role as a forcing factor of atmospheric CO2 and drives biospheric carbon dynamics. India is one of the largest GHGs emitters, yet less is understood in carbon cycling in terrestrial ecosystems. Here we explored the trend and magnitude of gross and net productivities of India for the last two decades (2000 – 2019) by integrating satellite observation from MODIS, remote sensing-based CASA model and twenty DGVMs from the TRENDY ensemble. Preliminary results exhibited a unimodal response across the data products with an overall positive trend and a declining decadal trend for 2010 – 2019. Alongside, the SPEI drought severity index across various ecological zones indicated India was more positively sensitive to wet span than the dry. We found that the ecosystems were drastically shifting their nature to C source with a positive trend in the productivities and were mediated by the changing climate. The analysis also revealed the increasing decadal amplitude of GPP by 0.0884 Pg C/Year, NBP by 0.0096 Pg C/Year, NEP by 0.0195 Pg C/Year, NPP by 0.0448 Pg C/Year and NEE by 0.0161 Pg C/Year. CASA underestimated the magnitudes but with the temporal synchronisation of the ensemble. Seasonal variability across the agro-ecological zones was more sensitive and was an offset for the declining productivities in the primaeval forests of India. The monsoon season contributed to the interannual variability of India. Higher uncertainty in productivities was observed in the high greening areas, whereas it contradicted NBP by reflecting a stable trend. Our results underscore the nature of C variability in the terrestrial ecosystems of India; and, they indicate that C release has reacted stronger than the C uptake, which was substantially inferred from NEE across the ecological zones.

Thunderstorms are very violent and short-lived weather phenomena associated with thunder, rain, heavy wind, lightning and dense clouds. These storms are persistent and intense during the pre-monsoon (March-May) season over Eastern and North-eastern India, leading to catastrophic destruction over the regions. These thunderstorms are locally known as Kal-Baishakhi, Bordoichila or Nor’westers, which are short-lived events able to make changes in the thermodynamic properties of the environment. In this work, thermodynamic indices were calculated and analysed to evaluate the spatial and temporal variations of thunderstorms over Eastern India (Odisha, Jharkhand and West Bengal). The present study also investigated the influence of climate change on thermodynamic indices thresholds over Eastern India by using radiosonde data and ERA-5. The thermodynamic indices considered in the study are Boyden index, bulk Richardson’s number, convective available potential energy, convective inhibition, cross totals index, dew point temperature at 850hPa, humidity Index, K index, lifted index, relative humidity at 700hPa, Showalter index, severe weather threat index, total totals index, vertical totals index. After calculating these indices, with the information of thunderstorm occurrence over the region, skill score analysis has been accomplished based on the contingency table. The work discussed the change in the thermodynamic indices pattern with every 5-year interval time for temporal variations and the climatological variation of thermodynamic indices by using spatial plots to differentiate the thunderstorm and non-thunderstorm days for spatial variations. In the temporal variation, some thermodynamic indices show a noticeable shift of threshold values over time, while some indices do not exhibit any apparent change in the pattern. The trend analysis of these thermodynamic indices shows evident changes in trends over the different regions of Eastern India for thunderstorm and non-thunderstorm days. Keywords: Thunderstorm, Climate Change, Thermodynamic indices, Radiosonde data, Skill score