Understanding the performance of the FLake model over two African Great Lakes

Thiery, W.; Martynov, Andrey; Darchambeau, F.; Descy, J.-P.; Plisnier, P.-D.; Sushama, L.; van Lipzig, N. P. M. (2014). Understanding the performance of the FLake model over two African Great Lakes. Geoscientific model development (GMD), 7(1), pp. 317-337. Copernicus Publications 10.5194/gmd-7-317-2014

[img]
Preview
Text
gmd-7-317-2014.pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (4MB) | Preview

The ability of the one-dimensional lake model FLake to represent the mixolimnion temperatures for tropical conditions was tested for three locations in East Africa: Lake Kivu and Lake Tanganyika's northern and southern basins. Meteorological observations from surrounding automatic weather stations were corrected and used to drive FLake, whereas a comprehensive set of water temperature profiles served to evaluate the model at each site. Careful forcing data correction and model configuration made it possible to reproduce the observed mixed layer seasonality at Lake Kivu and Lake Tanganyika (northern and southern basins), with correct representation of both the mixed layer depth and water temperatures. At Lake Kivu, mixolimnion temperatures predicted by FLake were found to be sensitive both to minimal variations in the external parameters and to small changes in the meteorological driving data, in particular wind velocity. In each case, small modifications may lead to a regime switch, from the correctly represented seasonal mixed layer deepening to either completely mixed or permanently stratified conditions from similar to 10 m downwards. In contrast, model temperatures were found to be robust close to the surface, with acceptable predictions of near-surface water temperatures even when the seasonal mixing regime is not reproduced. FLake can thus be a suitable tool to parameterise tropical lake water surface temperatures within atmospheric prediction models. Finally, FLake was used to attribute the seasonal mixing cycle at Lake Kivu to variations in the near-surface meteorological conditions. It was found that the annual mixing down to 60m during the main dry season is primarily due to enhanced lake evaporation and secondarily to the decreased incoming long wave radiation, both causing a significant heat loss from the lake surface and associated mixolimnion cooling.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography > Physical Geography > Unit Impact
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geography

UniBE Contributor:

Martynov, Andrey

Subjects:

500 Science > 550 Earth sciences & geology
900 History > 910 Geography & travel

ISSN:

1991-959X

Publisher:

Copernicus Publications

Language:

English

Submitter:

Monika Wälti-Stampfli

Date Deposited:

15 Sep 2014 16:28

Last Modified:

26 Jun 2016 01:52

Publisher DOI:

10.5194/gmd-7-317-2014

BORIS DOI:

10.7892/boris.52898

URI:

https://boris.unibe.ch/id/eprint/52898

Actions (login required)

Edit item Edit item
Provide Feedback