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Profile photo of Ronny Berndtsson

Ronny Berndtsson

Professor, Dep Director, MECW Dep Scientific Coordinator

Profile photo of Ronny Berndtsson

Modelling Lake Titicaca's daily and monthly evaporation

Author

  • Ramiro Pillco Zolá
  • Lars Bengtsson
  • Ronny Berndtsson
  • Belen Martí-Cardona
  • Frederic Satgé
  • Franck Timouk
  • Marie Paule Bonnet
  • Luis Mollericon
  • Cesar Gamarra
  • Jos Pasapera

Summary, in English

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.

Department/s

  • Division of Water Resources Engineering
  • Centre for Advanced Middle Eastern Studies (CMES)
  • MECW: The Middle East in the Contemporary World

Publishing year

2019-02-06

Language

English

Pages

657-668

Publication/Series

Hydrology and Earth System Sciences

Volume

23

Issue

2

Document type

Journal article

Publisher

European Geophysical Society

Topic

  • Oceanography, Hydrology, Water Resources

Status

Published

ISBN/ISSN/Other

  • ISSN: 1027-5606