Quantifying Impacts of Mean Annual Lake Bottom Temperature on Talik Development and Permafrost Degradation Below Expanding Thermokarst Lakes on the Qinghai-Tibet Plateau Page: 1
16 p.View a full description of this article.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
water MDPIT
Article
Quantifying Impacts of Mean Annual Lake Bottom
Temperature on Talik Development and Permafrost
Degradation below Expanding Thermokarst Lakes
on the Qinghai-Tibet Plateau
Feng Lingl1,2,* and Feifei Pan 2
1 School of Mathematics and Statistics, Zhaoqing University, Zhaoqing 526061, China
2 Department of Geography and the Environment, University of North Texas, Denton, TX 76203, USA;
feifei.pan@unt.edu
* Correspondence: lingf@zqu.edu.cn
check for
Received: 17 March 2019; Accepted: 29 March 2019; Published: 5 April 2019 updates
Abstract: Variations in thermokarst lake area, lake water depth, lake age, air temperature, permafrost
condition, and other environmental variables could have important influences on the mean annual
lake bottom temperature (MALBT) and thus affect the ground thermal regime and talik development
beneath the lakes through their direct impacts on the MALBT. A lake expanding model was employed
for examining the impacts of variations in the MALBT on talik development and permafrost
degradation beneath expanding thermokarst lakes in the Beiluhe Basin on the Qinghai-Tibetan
Plateau (QTP). All required boundary and initial conditions and model parameters were determined
based on field measurements. Four simulation cases were conducted with different respective fitting
sinusoidal functions of the MALBTs at 3.75 C, 4.5 C, 5.25 C, and 6.0 C. The simulated results
show that for lakes with MALBTs of 3.75 C, 4.5 C, 5.25 C, and 6.0 C, the maximum thicknesses of
bowl-shaped talik below the lakes at year 300 were 27.2 m, 29.6 m, 32.0 m, and 34.4 m; funnel-shaped
open taliks formed beneath the lakes at years 451, 411, 382, and 356 after the formation of thermokarst
lakes, with mean downward thaw rates of 9.1 m/year, 10.2 m/year, 11.2 m/year, and 12.0 m/year,
respectively. Increases in the MALBT from 3.75 C to 4.52 C, 4.25 C to 5.25 C, and 5.25 C to 6.0 C
respectively resulted in the permafrost with a horizontal distance to lake centerline less than or equal
to 45 m thawing completely 36 years, 32 years, and 24 years in advance, and the maximum ground
temperature increases at a depth of 40 m below the lakes at year 600 ranged from 2.16 C to 2.80 C,
3.57 C, and 4.09 C, depending on the MALBT. The ground temperature increases of more than
0.5 C at a depth of 40 m in year 600 occurred as far as 74.9 m, 87.2 m, 97.8 m, and 106.6 m from the
lake centerlines. The simulation results also show that changes in the MALBT almost have no impact
on the open talik lateral progress rate, although the minimum distances from the open talik profile to
lake centerlines below the lakes with different MALBTs exhibited substantial differences.
Keywords: mean annual lake bottom temperature (MALBT); open talik; permafrost degradation;
numerical simulation; Qinghai-Tibetan Plateau (QTP)
1. Introduction
Thermokarst lakes are a unique natural part of the landscape of the high-latitude and high-altituderegions where ice-rich permafrost exists. The impacts of thermokarst lakes on the permafrost thermal
regime and underlying talik progress have been widely studied by many researchers during the past
several decades because thermokarst lakes are (1) important heat sources for the ground surrounding
the lakes [1-7]; (2) major producers of methane if taliks develop under the lakes [8-12]; and (3)Water 2019, 11, 706; doi:10.3390/w11040706
www.mdpi.com/journal/water
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Ling, Feng & Pan, Feifei. Quantifying Impacts of Mean Annual Lake Bottom Temperature on Talik Development and Permafrost Degradation Below Expanding Thermokarst Lakes on the Qinghai-Tibet Plateau, article, April 5, 2019; [Basel, Switzerland]. (https://digital.library.unt.edu/ark:/67531/metadc1638169/m1/1/: accessed July 17, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting University of North Texas.