Global Climate Change In The Indian Monsoon

Introduction

Variations in the global climate has been phenomena observed in the past as well as in the present, but now it has been treated as a serious issue by people all around the world from scientists to policy makers and layman everyone speak about the climate change in the current century. The variations in the global temperate have been keenly watched over especially in the last few decades. According to the Fifth Assessment report of IPCC (2013) the global average temperature has increased by 0.85˚ since 1880 to 2013.But the change in the climate varies from place to place and the need for policies to adapt or the urgency to adapt differs from one place to another. Various researches have been going on all over the world to assess

When the historical data of precipitation between the years 1900-2005 has been reconstructed using different climate models the overall global precipitation showed an increasing trend. However regional trends are observed to differ especially over the regions near the equator (RenLi, et. al, 2013).Major amount of precipitation in India is received from the monsoon. The Indian Monsoon is popularly categorized as the Southwest Monsoon (June-September) and Northeast Monsoon (October-December). Among the Two monsoons the southwest monsoon is the major contributor of rainfall in India, Its contribution accounts for more than 70% of the total rainfall to India. The southwest monsoon is described as a cross-equatorial low level jet stream carrying the moisture generated by the trade winds over the south Indian ocean and the Arabian Sea which supports the June – September monsoon rainfall in India (Joseph P V and Simon A 2005). Major portion of the country receives rainfall during the Southwest monsoon. The North east monsoon is also known as the Post-Monsoon Season or the Retreating Monsoon. Northeast Monsoon season is the major period of rainfall activity over south peninsula, particularly in

This unequal heating produces difference in pressure in different parts of the earth and when the atmosphere tries to equalize the pressure by shifting the air masses from high pressure to low pressure wind is developed. So the measurement of the wind speed and also knowing its direction plays a critical role in the prediction of the weather. The wind speed is one of the primary factors which drive the evaporation process on the earth. The wind speed in our study area is showing a steep decreasing trend over the 40 years. The data suggests that the wind speed was high during the 1970 's when it was recorded 16km/h on an average during a year, during the 1980 's the mean annual wind speed gradually went down then in the early 90 's it mean annual wind speed of the region saw an increase and again it started declining in the later in 90 's and went down to the worse in 2000 's where on an average it was recorded to be 5.6 km/h. Based on the summary of the various studies conducted all over the world on the changing wind speeds it has been found that there is a decline in surface wind speed over many other parts of the world such as Australia, Africa, East Asia, South East and Central Asia, North, Central and South America and Germany. While the mean annual variability in the wind speed has been analyzed based on the data obtained from nearly 58 stations in India, it has been found that the data is