#Caspian_Sea evaporating as temperatures rise, study finds
▻http://news.agu.org/press-release/caspian-sea-evaporating-as-temperatures-rise-study-finds
▻http://sites.agu.org/files/2017/08/The-Caspian-Sea-from-Space.jpg
Earth’s largest inland body of water has been slowly evaporating for the past two decades due to rising temperatures associated with climate change, a new study finds.
Water levels in the Caspian Sea dropped nearly 7 centimeters (3 inches) per year from 1996 to 2015, or nearly 1.5 meters (5 feet) total, according to the new study. The current Caspian Sea level is only about 1 meter (3 feet) above the historic low level it reached in the late 1970s.
Increased evaporation over the Caspian Sea has been linked to increased surface air temperatures. According to the data from the study, the average yearly surface temperature over the Caspian Sea rose by about 1 degree Celsius (1.8 degrees Fahrenheit) between the two time frames studied, 1979-1995 and 1996-2015. These rising temperatures are likely a result of climate change, according to the study’s authors.
Evaporation brought about by warming temperatures appears to be the primary cause of the current drop in sea level and the decline will likely continue as the planet warms, according to the study’s authors.
“From our point of view as geoscientists, it’s an interesting place because it’s possible to construct a sort of budget for the total amount of water that’s there,” said Clark Wilson, a geophysicist with the Jackson School of Geosciences at the University of Texas at Austin, and co-author of the new study published in Geophysical Research Letters, a journal of the American Geophysical Union. “The real control that causes it to go up and down over long periods of time is really most likely the evaporation, which is almost completely dominated by temperature.”
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Le résumé de l’article (sous #paywall)
Long-term Caspian Sea level change - Chen - 2017 - Geophysical Research Letters - Wiley Online Library
▻http://onlinelibrary.wiley.com/doi/10.1002/2017GL073958/full
Caspian Sea level (CSL) has undergone substantial fluctuations during the past several hundred years. The causes over the entire historical period are uncertain, but we investigate here large changes seen in the past several decades. We use climate model-predicted precipitation (P), evaporation (E), and observed river runoff (R) to reconstruct long-term CSL changes for 1979–2015 and show that PER (P-E + R) flux predictions agree very well with observed CSL changes. The observed rapid CSL increase (about 12.74 cm/yr) and significant drop (~−6.72 cm/yr) during the periods 1979–1995 and 1996–2015 are well accounted for by integrated PER flux predictions of ~+12.38 and ~−6.79 cm/yr, respectively. We show that increased evaporation rates over the Caspian Sea play a dominant role in reversing the increasing trend in CSL during the past 37 years. The current long-term decline in CSL is expected to continue into the foreseeable future, under global warming scenarios.
Sans doute le bon endroit pour signaler cet excellent petit ouvrage en pdf :
▻https://gridarendal-website.s3.amazonaws.com/production/documents/:s_document/238/original/vitalcaspian.pdf?1487683190
#merci !
Comme tu t’en doutes, en ce qui me concerne, j’ai téléchargé cet excellent ouvrage depuis belle lurette !
Il a déjà été signalé (par toi) ici en mai 2013, mais sous une autre adresse (qui ne passe pas par Amazon et ses AWS :-P
Ici ▻https://seenthis.net/messages/143393
et là ►https://seenthis.net/messages/143202
mais c’est en effet une excellente occasion de le rappeler.