Impact of Seasonal Low on Sea Level Rise

Mirza Jawwad Baig,M Jawed Iqbal,Saba Naz

doi:10.4236/ijg.2019.101003

Abstract

Every region around the globe has its unique climatic conditions which are set based on different orographic constant and atmospheric dynamic features. These features posses’ variability on different time scales. Determining the local sea level change based on terrestrial non-tidal, short-term variability is complicated. Some internal mechanisms of ocean are also taking place along with the external physical ones. We show that variability at Sindh-Baluchistan coastal belt can be greatly explained via dimensional indices of the position and intensity of the atmospheric center of action (COAs). This technique has already proved its usefulness at number of location especially in Northern Atlantic. It takes into account the changes in the atmospheric pressure which is exerted on the sea surface influencing the variability in sea level on seasonal scale and on inter-annual basis. As warming causes thermal expansion of water it also causes changes in atmospheric circulation. Both of these processes affect the sea level variability on their respective time scales. Atmospheric being the quicker one of the two to pass on the effect is also more influential to explain the variability in local sea level. In this attempt the COA approach is used to assess the impact of low pressure on local sea levels.

Highlights

During the last 3 millennium, the mean sea level has been below today’s observed values
Sea level rises due to a thermal expansion of the ocean which contributes about 40% in current sea levels changes while the 60% [2] [3] is due to melting of glaciers and ice sheets as the global warming continues
We have used the center of action (COA) approach for South Asia low pressure (SALP), which develops in summer time

Summary

Introduction

During the last 3 millennium, the mean sea level has been below today’s observed values. Sea level rises due to a thermal expansion of the ocean which contributes about 40% in current sea levels changes while the 60% [2] [3] is due to melting of glaciers and ice sheets as the global warming continues This calls for the coastal flooding which disturbs the socio-economic structure of the society [4]. This study is an attempt for investigating the possible impact of South Asian low heat on the variability of local sea level for Karachi coast using the centers of action (COA) approach [5]. An attempt is made to explain the physical mechanisms to establish the relationships between the South Asian low heat and sea level variability by examining the composite maps of large-scale circulation fields using NCEP/NCAR Reanalysis data. On the basis of previous results and possible physical mechanism the conclusion is made

Preprocessing of Data

Methodology

Regressions and Correlations Results

Mechanisms for the Relationships between COA and Sea Level Variability

Findings

Conclusion