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Modelling Lake Titicaca's daily and monthly evaporation

Pillco Zolá, Ramiro LU ; Bengtsson, Lars LU ; Berndtsson, Ronny LU ; Martí-Cardona, Belen ; Satgé, Frederic ; Timouk, Franck ; Bonnet, Marie Paule ; Mollericon, Luis ; Gamarra, Cesar and Pasapera, Jos (2019) In Hydrology and Earth System Sciences 23(2). p.657-668
Abstract

Lake Titicaca is a crucial water resource in the central part of the Andean mountain range, and it is one of the lakes most affected by climate warming. Since surface evaporation explains most of the lake's water losses, reliable estimates are paramount to the prediction of global warming impacts on Lake Titicaca and to the region's water resource planning and adaptation to climate change. Evaporation estimates were done in the past at monthly time steps and using the four methods as follows: water balance, heat balance, and the mass transfer and Penman's equations. The obtained annual evaporation values showed significant dispersion. This study used new, daily frequency hydro-meteorological measurements. Evaporation losses were... (More)

Lake Titicaca is a crucial water resource in the central part of the Andean mountain range, and it is one of the lakes most affected by climate warming. Since surface evaporation explains most of the lake's water losses, reliable estimates are paramount to the prediction of global warming impacts on Lake Titicaca and to the region's water resource planning and adaptation to climate change. Evaporation estimates were done in the past at monthly time steps and using the four methods as follows: water balance, heat balance, and the mass transfer and Penman's equations. The obtained annual evaporation values showed significant dispersion. This study used new, daily frequency hydro-meteorological measurements. Evaporation losses were calculated following the mentioned methods using both daily records and their monthly averages to assess the impact of higher temporal resolution data in the evaporation estimates. Changes in the lake heat storage needed for the heat balance method were estimated based on the morning water surface temperature, because convection during nights results in a well-mixed top layer every morning over a constant temperature depth. We found that the most reliable method for determining the annual lake evaporation was the heat balance approach, although the Penman equation allows for an easier implementation based on generally available meteorological parameters. The mean annual lake evaporation was found to be 1700&thinsp;mm&thinsp;year<span classCombining double low line"inline-formula'1</span>. This value is considered an upper limit of the annual evaporation, since the main study period was abnormally warm. The obtained upper limit lowers by 200&thinsp;mm&thinsp;year<span classCombining double low line"inline-formula">ĝ'1</span>, the highest evaporation estimation obtained previously, thus reducing the uncertainty in the actual value. Regarding the evaporation estimates using daily and monthly averages, these resulted in minor differences for all methodologies.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Hydrology and Earth System Sciences
volume
23
issue
2
pages
12 pages
publisher
European Geophysical Society
external identifiers
  • scopus:85061238424
ISSN
1027-5606
DOI
10.5194/hess-23-657-2019
language
English
LU publication?
yes
id
8df88d2a-d584-40ad-bf6d-465beeabea48
date added to LUP
2019-02-19 10:08:07
date last changed
2020-01-13 01:29:47
@article{8df88d2a-d584-40ad-bf6d-465beeabea48,
  abstract     = {<p/><p>Lake Titicaca is a crucial water resource in the central part of the Andean mountain range, and it is one of the lakes most affected by climate warming. Since surface evaporation explains most of the lake's water losses, reliable estimates are paramount to the prediction of global warming impacts on Lake Titicaca and to the region's water resource planning and adaptation to climate change. Evaporation estimates were done in the past at monthly time steps and using the four methods as follows: water balance, heat balance, and the mass transfer and Penman's equations. The obtained annual evaporation values showed significant dispersion. This study used new, daily frequency hydro-meteorological measurements. Evaporation losses were calculated following the mentioned methods using both daily records and their monthly averages to assess the impact of higher temporal resolution data in the evaporation estimates. Changes in the lake heat storage needed for the heat balance method were estimated based on the morning water surface temperature, because convection during nights results in a well-mixed top layer every morning over a constant temperature depth. We found that the most reliable method for determining the annual lake evaporation was the heat balance approach, although the Penman equation allows for an easier implementation based on generally available meteorological parameters. The mean annual lake evaporation was found to be 1700&amp;thinsp;mm&amp;thinsp;year&lt;span classCombining double low line"inline-formula'1&lt;/span&gt;. This value is considered an upper limit of the annual evaporation, since the main study period was abnormally warm. The obtained upper limit lowers by 200&amp;thinsp;mm&amp;thinsp;year&lt;span classCombining double low line"inline-formula"&gt;ĝ'1&lt;/span&gt;, the highest evaporation estimation obtained previously, thus reducing the uncertainty in the actual value. Regarding the evaporation estimates using daily and monthly averages, these resulted in minor differences for all methodologies.</p>},
  author       = {Pillco Zolá, Ramiro and Bengtsson, Lars and Berndtsson, Ronny and Martí-Cardona, Belen and Satgé, Frederic and Timouk, Franck and Bonnet, Marie Paule and Mollericon, Luis and Gamarra, Cesar and Pasapera, Jos},
  issn         = {1027-5606},
  language     = {eng},
  month        = {02},
  number       = {2},
  pages        = {657--668},
  publisher    = {European Geophysical Society},
  series       = {Hydrology and Earth System Sciences},
  title        = {Modelling Lake Titicaca's daily and monthly evaporation},
  url          = {http://dx.doi.org/10.5194/hess-23-657-2019},
  doi          = {10.5194/hess-23-657-2019},
  volume       = {23},
  year         = {2019},
}