Study of Sea Surface Temperature (SST) and Sea Level Rise (SLR) Along Karachi Coast using Satellite Data, Pakistan

Abstract

The rising temperature due to climate change leads to glaciers melting, causing increased sea levels and sea surface temperatures (SST). The rising SST and glacier melting elevate sea levels around the globe. The rising sea level is hazardous for the coastal regions worldwide, and therefore, calls for continuous monitoring to manage this threat. Pakistan, with a coastline of 990 km long, is among those countries most vulnerable to sea-level rise (SLR). Around 10% of Pakistan's population lives near the coastal zones, which are most marginalized and dependent on fishing and small agricultural farms. An SLR of a few millimeters per year is a serious threat to Pakistan's coastal areas that can, directly and indirectly, cause land loss of low-lying areas and destruction of infrastructures, human settlements, agricultural lands, and coastal ecosystems, and other resources. The coastal communities of developing countries such as Pakistan, lacking essential resources, are the most disadvantageous and adversely affected people of the world due to these disasters. To overcome resources and capacity constraints, remote sensing (RS) and Geographic Information System (GIS) techniques can be employed to monitor coastal zones at larger extents. In this study, SLR and SST around the coast of Karachi have been investigated using multi-mission satellite radar altimetry (SRA) and MODIS Terra L3 SST product. The SRA is used to monitor sea levels using data from 1993 to 2018. Similarly, monthly SST data from 2000 to 2019 have been acquired to monitor SST trends. The rising sea levels and temperatures were estimated at 3.9 mm/year and 0.0138 °C/year, respectively. Different extrapolation techniques can further be utilized to predict the potential of SLR and SST in the study area for developing future coastal zone management plans.

Sea-Level Rise in Pakistan: Recommendations for Strengthening Evidence-Based Coastal Decision-Making

“…Since satellite altimetry measures geocentric sea-level rise (which does not include vertical movement of the shore coastal land surface), subtracting satellite altimetry observations from tide gauge data can also be used to understand vertical land movement (for details, see [35,36]). In Pakistan, tide gauge data co-located with GNSS does not yet exist, and there are limited studies using satellite altimetry in sea-level trend analysis (e.g., [37]). Therefore, there is scope for these methods to be better integrated into research across disciplines.…”