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Kumar, V., Jana, S., Bhardwaj, A., Deepa, R., Sahu, S. K., Pradhan, P. K., et al. (2018). Greenhouse Gas Emission, Rainfall and Crop Production Over North-Western India. TOECOLJ, 11(1), 47–61.
This study is based on datasets acquired from multi sources e.g. rain-gauges, satellite, reanalysis and coupled model for the region of Northwestern India. The influence of rainfall on crop production is obvious and direct. With the climate change and global warming, greenhouse gases are also showing an adverse impact on crop production. Greenhouse gases (e.g. CO2, NO2 and CH4) have shown an increasing trend over Northwestern Indian region. In recent years, rainfall has also shown an increasing trend over Northwestern India, while the production of rice and maize are reducing over the region. From eight selected sites, over Northwestern India, where rice and maize productions have reduced by 40%, with an increase in CO2, NO2 and CH4 gas emission by 5% from 1998 to 2011.
The correlation from one year to another between rainfall, gas emission and crop production was not very robust throughout the study period, but seemed to be stronger for some years than others.
Such trends and crop yield are attributed to rainfall, greenhouse gas emissions and to the climate variability.
|Li, H., & Misra, V. (2014). Thirty-two-year ocean-atmosphere coupled downscaling of global reanalysis over the Intra-American Seas. Clim Dyn, 43(9-10), 2471–2489.|
|Lim, Y. - K., & Kim, K. - Y. (2006). A New Perspective on the Climate Prediction of Asian Summer Monsoon Precipitation. J. Climate, 19(19), 4840–4853.|
|Lu, J., Hu, A., & Zeng, Z. (2014). On the possible interaction between internal climate variability and forced climate change. Geophys. Res. Lett., 41(8), 2962–2970.|
|Michael, J. - P., Misra, V., & Chassignet, E. P. (2013). The El Niño and Southern Oscillation in the historical centennial integrations of the new generation of climate models. Reg Environ Change, 13(S1), 121–130.|
Misra, V., & Bhardwaj, A. (2019). Defining the Northeast Monsoon of India. Mon. Wea. Rev., 147(3), 791–807.
Abstract: This study introduces an objective definition for onset and demise of the Northeast Indian Monsoon (NEM). The definition is based on the land surface temperature analysis over the Indian subcontinent. It is diagnosed from the inflection points in the daily anomaly cumulative curve of the area-averaged surface temperature over the provinces of Andhra Pradesh, Rayalseema, and Tamil Nadu located in the southeastern part of India. Per this definition, the climatological onset and demise dates of the NEM season are 6 November and 13 March, respectively. The composite evolution of the seasonal cycle of 850hPa winds, surface wind stress, surface ocean currents, and upper ocean heat content suggest a seasonal shift around the time of the diagnosed onset and demise dates of the NEM season. The interannual variations indicate onset date variations have a larger impact than demise date variations on the seasonal length, seasonal anomalies of rainfall, and surface temperature of the NEM. Furthermore, it is shown that warm El Niño�Southern Oscillation (ENSO) episodes are associated with excess seasonal rainfall, warm seasonal land surface temperature anomalies, and reduced lengths of the NEM season. Likewise, cold ENSO episodes are likely to be related to seasonal deficit rainfall anomalies, cold land surface temperature anomalies, and increased lengths of the NEM season.
|Misra, V., & Dirmeyer, P. A. (2009). Air, Sea, and Land Interactions of the Continental U.S. Hydroclimate. J. Hydrometeor, 10(2), 353–373.|
|Morey, S. L., Dukhovskoy, D. S., & Bourassa, M. A. (2009). Connectivity of the Apalachicola River flow variability and the physical and bio-optical oceanic properties of the northern West Florida Shelf. Continental Shelf Research, 29(9), 1264–1275.|
Morrison, T., Dukhovskoy, D. S., McClean, J., Gille, S. T., & Chassignet, E. (2018). Causes of the anomalous heat flux onto the Greenland continental shelf. In American Geophysical Union (Vol. Fall Meeting).
Abstract: On the continental shelf around Greenland, warm-salty Atlantic water at depth fills the deep narrow fjords where Greenland's tidewater glaciers terminate. Changes in the quantity or properties of this water mass starting in the mid 1990s is thought to be largely responsible for increased ocean-driven melting of the Greenland Ice Sheet. Using high-resolution (nominal 0.1-degree) ocean circulation models we cannot accurately resolve small-scale processes on the shelf or within fjords. However, we can assess changes in the flux of heat via Atlantic water onto the continental shelf. To understand the causes of the anomalous heat that has reached the shelf we examine heat content of subtropical gyre water and shifts in the North Atlantic and Atlantic Multidecadal Oscillations.
We compare changes in heat transport in two eddy permitting simulations: a global 0.1 degree (5-7km around Greenland) resolution coupled hindcast (1970-2009) simulation of the Parallel Ocean Program (POP) and a regional 0.08 degree (3-5km around Greenland) resolution coupled HYbrid Coordinate Ocean Model (HYCOM) hindcast (1993-2016) simulation. Both models are coupled to the Los Alamos National Laboratory Community Ice CodE version 4 and forced by atmospheric reanalysis fluxes. In both models we look for processes that could explain the increase in heat; processes that are present in both are likely to be robust causes of warming.
Keywords: 0726 Ice sheets, CRYOSPHEREDE: 4207 Arctic and Antarctic oceanography, OCEANOGRAPHY: GENERALDE: 4215 Climate and interannual variability, OCEANOGRAPHY: GENERALDE: 4255 Numerical modeling, OCEANOGRAPHY: GENERAL
Morrow, R. M., Ohman, M. D., Goericke, R., Kelly, T. B., Stephens, B. M., & Stukel, M. R. (2018). CCE V: Primary production, mesozooplankton grazing, and the biological pump in the California Current Ecosystem: Variability and response to El Niño. Deep Sea Research Part I: Oceanographic Research Papers, 140, 52–62.
Abstract: Predicting marine carbon sequestration in a changing climate requires mechanistic understanding of the processes controlling sinking particle flux under different climatic conditions. The recent occurrence of a warm anomaly (2014-2015) followed by an El Nino (2015-2016) in the southern sector of the California Current System presented an opportunity to analyze changes in the biological carbon pump in response to altered climate forcing. We compare primary production, mesozooplankton grazing, and carbon export from the euphotic zone during quasi-Lagrangian experiments conducted in contrasting conditions: two cruises during warm years – one during the warm anomaly in 2014 and one toward the end of El Nino 2016 – and three cruises during El Ninoneutral years. Results showed no substantial differences in the relationships between vertical carbon export and its presumed drivers (primary production, mesozooplankton grazing) between warm and neutral years. Mesozooplankton fecal pellet enumeration and phaeopigment measurements both showed that fecal pellets were the dominant contributor to export in productive upwelling regions. In more oligotrophic regions, fluxes were dominated by amorphous marine snow with negligible pigment content. We found no evidence for a significant shift in the relationship between mesozooplankton grazing rate and chlorophyll concentration. However, massspecific grazing rates were lower at low-to-moderate chlorophyll concentrations during warm years relative to neutral years. We also detected a significant difference in the relationship between phytoplankton primary production and photosynthetically active radiation between years: at similar irradiance and nutrient concentrations, productivity decreased during the warm events. Whether these changes resulted from species composition changes remains to be determined. Overall, our results suggest that the processes driving export remain similar during different climate conditions, but that species compositional changes or other structural changes require further attention.
Keywords: Carbon export; Fecal pellets; Sinking particles; Interannual variability; Net primary productivity; Eastern boundary upwelling system KeyWords Plus:ZOOPLANKTON FECAL PELLETS; NORTH PACIFIC-OCEAN; CURRENT SYSTEM; SOUTHERN CALIFORNIA; UNDERWATER GLIDERS; CARBON EXPORT; ZONE; CHLOROPHYLL; STABILITY; EQUATIONS