Absence of Surface Water Temperature Trends in Lake Kinneret despite Present Atmospheric Warming: Comparisons with Dead Sea Trends

Pavel Kishcha,Boris Starobinets,Pinhas Alpert,Yury Lechinsky

doi:10.3390/rs13173461

Pavel Kishcha, Boris Starobinets + Show 2 more

Open Access

https://doi.org/10.3390/rs13173461

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Abstract

This study was carried out using Moderate Resolution Imaging Spectroradiometer (MODIS) 1 km × 1 km resolution records on board Terra and Aqua satellites and in-situ measurements during the period (2003–2019). In spite of the presence of increasing atmospheric warming, in summer when evaporation is maximal, in fresh-water Lake Kinneret, satellite data revealed the absence of surface water temperature (SWT) trends. The absence of SWT trends in the presence of increasing atmospheric warming is an indication of the influence of increasing evaporation on SWT trends. The increasing water cooling, due to the above-mentioned increasing evaporation, compensated for increasing heating of surface water by regional atmospheric warming, resulting in the absence of SWT trends. In contrast to fresh-water Lake Kinneret, in the hypersaline Dead Sea, located ~100 km apart, MODIS records showed an increasing trend of 0.8 °C decade−1 in summer SWT during the same study period. The presence of increasing SWT trends in the presence of increasing atmospheric warming is an indication of the absence of steadily increasing evaporation in the Dead Sea. This is supported by a constant drop in Dead Sea water level at the rate of ~1 m/year from year to year during the last 25-year period (1995–2020). In summer, in contrast to satellite measurements, in-situ measurements of near-surface water temperature in Lake Kinneret showed an increasing trend of 0.7 °C decade−1.

Highlights

Lake surface water temperature (SWT) is one of the main factors determining evaporation and, energy and moisture exchange at the air-water interface
As a consequence of the air being in contact with the lake water surface, SWT is sensitive to atmospheric warming
We investigated long-term trends of surface water temperature in Lake Kinneret focusing on the region (32.67◦ N–32.93◦ N, 35.46◦ E–35.71◦ E) covering the lake and surrounding land areas (Figure 1)

Summary

Introduction

Lake surface water temperature (SWT) is one of the main factors determining evaporation and, energy and moisture exchange at the air-water interface. Air warming in the overlying atmosphere is reflected in lake surface water temperature as well as in water temperature below the surface. This has potential consequences for a broad range of physical and ecological factors such as thermal structure; lake productivity and ecosystems, in accordance with Adrian et al [1] and Williamson et al [2]. This highlights the importance of investigating long-term lake surface water temperature trends. That study was carried out using MODIS data of 5 km × 5 km resolution during the period 2000–2016

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