Modelling Lake Titicaca's daily and monthly evaporation

Research output: Contribution to journalArticle

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 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.

Details

Authors
  • Ramiro Pillco Zolá
  • Lars Bengtsson
  • Ronny Berndtsson
  • Belen Martí-Cardona
  • Frederic Satgé
  • Franck Timouk
  • Marie Paule Bonnet
  • Luis Mollericon
  • Cesar Gamarra
  • Jos Pasapera
Organisations
External organisations
  • Higher University of San Andrés
  • University of Surrey
  • University of Montpellier
  • Université Paul Sabatier
  • Instituto del Mar del Peru (IMARPE)
  • Espace pour le Développement (ESPACE-DEV)
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Oceanography, Hydrology, Water Resources
Original languageEnglish
Pages (from-to)657-668
Number of pages12
JournalHydrology and Earth System Sciences
Volume23
Issue number2
Publication statusPublished - 2019 Feb 6
Publication categoryResearch
Peer-reviewedYes