Estimating surface temperature changes of lakes in the Tibetan Plateau using MODIS LST data

Abstract

Temperature changes over the Tibetan Plateau (TP) exhibit a dependence on altitude, as observed from meteorological station data and Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) data. However, little is known about the changes in water surface temperature (WST) of lakes in the TP under the warming climate conditions over the past few decades. In this study, lake WST was examined using a MODIS/Terra 8 day LST (nighttime) product (MOD11A2) over the period 2001-2012. It was found that 52 lakes included in the analysis of WST exhibited an average rate of change of 0.012 ± 0.033°C/yr. Of these 52 lakes, 31 lakes (60%) displayed a temperature increase with a mean warming rate of 0.055 ± 0.033°C/yr and 21 lakes (40%) displayed a temperature decrease with a mean cooling rate of À0.053 ± 0.038°C/yr. The rates of change in WST for 13 lakes were statistically significant, and these included nine warming and four cooling lakes. Of the 17 lakes with nearby weather stations, nine lakes (53%) showed faster warming than nearby air/land. The warming lakes could be attributed to locally rising air and land surface temperatures as well as other factors such as the decreased lake ice cover. The cooling lakes were mostly located at high elevations (>4200 m), and the trend could have been due to increased cold water discharge to the lakes from accelerated glacier/snow melts. Therefore, both warming and cooling lake temperatures in the TP were possibly the result of increased air temperatures (0.036 ± 0.027°C/yr) under global warming conditions.

Spatiotemporal Variations of Lake Surface Temperature across the Tibetan Plateau Using MODIS LST Product

“…More effective images were identified from April to June, and September to mid-December. Furthermore, more effective images were also found from the nighttime MODIS LST product ( Figure S3), which is consistent with the findings from other investigations [12,20,26].…”

“…In addition, ice break-up, freeze-up date, and ice-free duration having direct connection with LWST, were also calculated through counting the accumulative days of the mean temperature ((daytime + nighttime)/2) above, below 0 • C for each of the 56 lakes concerned, where the median of the Julian Day for each 8-day composite was considered for accumulative days counting. Further, to track the temporal trend of LSWT for each of the 56 lakes, the rate of temperature annual change from MODIS LST data was regressed against the data acquisition year using the following regression model [20]:…”

Tributaries affect the thermal response of lakes to climate change

“…This response applies to aquatic systems in which a difference exists in temperature and heating regimes between rivers and lakes, but does not appear to affect water bodies with uniform temperature/heating regimes. Our results thus supports the hypothesis put forward by Zhang et al (2014), stating that climate warming of lakes might be reduced and even reversed by addition of external water.…”

An Investigation of Ice Surface Albedo and Its Influence on the High-Altitude Lakes of the Tibetan Plateau

“…Many studies have shown that the MODIS land surface temperature product has good accuracy [9,42,43].…”

“…Land surface temperature (LST) is the key factor regulating the exchange of energy and water in the air-lake interface [8]. In the TP, a few studies have shown that the LST rises even faster than regional air temperature in summer [9]. These lakes are located on the third pole of the Earth, where the cold climate leads to a long frozen period (four to six months) for the TP lakes [10].…”