Citizen science shows systematic changes in the temperature difference between air and inland waters with global warming

TitleCitizen science shows systematic changes in the temperature difference between air and inland waters with global warming
Publication TypeJournal Article
Year of Publication2017
AuthorsWeyhenmeyer GA, Mackay M, Stockwell JD, Thiery W, Grossart H-P, Augusto-Silva PB, Baulch HM, de Eyto E, Hejzlar J, Kangur K, Kirillin G, Pierson DC, Rusak JA, Sadro S, R. Woolway I
JournalScientific Reports
Volume7
Pagination43890 -
Date Published03/2017
Abstract

Citizen science projects have a long history in ecological studies. The research usefulness of such projects is dependent on applying simple and standardized methods. Here, we conducted a citizen science project that involved more than 3500 Swedish high school students to examine the temperature difference between surface water and the overlying air (Tw-Ta) as a proxy for sensible heat flux (QH). If QH is directed upward, corresponding to positive Tw-Ta, it can enhance CO2 and CH4 emissions from inland waters, thereby contributing to increased greenhouse gas concentrations in the atmosphere. The students found mostly negative Tw-Ta across small ponds, lakes, streams/rivers and the sea shore (i.e. downward QH), with Tw-Ta becoming increasingly negative with increasing Ta. Further examination of Tw-Ta using high-frequency temperature data from inland waters across the globe confirmed that Tw-Ta is linearly related to Ta. Using the longest available high-frequency temperature time series from Lake Erken, Sweden, we found a rapid increase in the occasions of negative Tw-Ta with increasing annual mean Ta since 1989. From these results, we can expect that ongoing and projected global warming will result in increasingly negative Tw-Ta, thereby reducing CO2 and CH4 transfer velocities from inland waters into the atmosphere.

URLhttp://dx.doi.org/10.1038/srep43890