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Investigation of micro climate and energy balance along a stream

Subproject of: Potential of riparian vegetation to mitigate effects of climate change on biological assemblages of small and medium sized running waters (BIO_CLIC)

Project Leader
Weihs Philipp, BOKU Project Leader
Contact person:
Trimmel Heidelinde
Duration:
01.03.2012-31.03.2015
Programme:
Austrian Climate Research Programme (ACRP) - Individual Project
Type of Research
Applied Research
Staff
Trimmel Heidelinde, Project Staff
Kalny Gerda, Project Staff (bis 31.01.2021)
Leidinger David, Project Staff
Gangneux Clément, Project Staff (bis 30.09.2015)
BOKU Research Units
Institute of Hydrobiology and Aquatic Ecosystem Management (IHG)
Institute of Meteorology and Climatology
Institute of Soil Bioengineering and Landscape Construction
Funded by
Klima- und Energiefonds, Leopold-Ungar-Platz 2 / Stiege 1 / 4.OG / Top 142, 1190 Wien, Austria
Abstract
This sub-project of the ACRP project Bio_Clic deals first with the experimental characterisation of the riparian micro climate and of the energy balance of the stream. In a second step the experimental data are used to validate a stream energy balance model.

To determine the above stream microclimate and the inherent microclimate in the riparian vegetation plots, routine measurements of air temperature and air humidity, wind speed, shortwave and longwave radiation balance (ingoing and outgoing radiation flux) will be performed. To characterize the stream surface energy exchange following parameters will be measured: firstly the river will be characterized by measuring stream flow, stream depth and width and surrounding riparian vegetation. Secondly routine measurements of water temperature in three different depths
and of the bed sediment temperature (to determine sediment heat exchange) will be performed. The data of the CR1000 datalogger (4Mb storage capacity) will be read out regularly (every 3 months) at the site. On this occasion some additional measurements of water transmissivity and measurements to characterize the inhomogeneities of the measured parameters (water temperature, solar radiation and wind) will be performed.

The stream energy balance modelling will be performed with the program HEATSOURCE.
The total net heat flux into or out of a stream is the sum of the shortwave radiation balance, of the longwave radiation balance, of the latent heat flux, of the convection heat flux at the air water interface and of the streambed conduction. The radiation balance code needs firstly to account for the influence of riparian vegetation on shortwave and longwave radiation balance.
Two different approaches will be compared for this radiation subroutine: 1) a gap light analyzer technique and 2) a canopy shade factor approach which requires the exact dimensions of the surrounding canopy as well as the angle of the horizon at all sky directions. The radiation code will be validated using the radiation measurements and fish eye photographs performed within the field surveys.
The stream energy balance model will be tested using different approaches for the calculation of evaporative heat loss, sensible heat loss and water absorption. For calculation of the evaporative heat loss a Penman type method will be compared with a mass transfer method and an energy budget method. Sensible heat will be calculated
using a bowen ratio method and a temperature gradient method. The stream energy balance model also includes the water absorption calculated using some empirical equation obtained with measurements, and it also takes into account the streambed heat conduction.
Keywords
climatology; meteorology;
Energiebilanz; Stream; Radiation balance;
Publications

Philipp Weihs, Heidelinde Trimmel, Herbert Formayer, Gerda Kalny, Hans Peter Rauch, and David Leidinger (1) (2016): Investigation of the impact of climate change on river water temperature:possible mitigation measures using riparian vegetation.
[European Geosciences Union EGU General Assembly 2016, Vienna, Austria, 17.04.2016 - 22.04.2016]

, Geophysical Research Abstracts, 18, 8002-8002

Weihs, P., Trimmel, H., Hasel, S., Mursch-Radlgruber, A. (2015): Messung und Modellierung der Wassertemperatur an den Flüssen Lafnitz und Pinka.
[ÖWAV Ingenieurbiologie 2015 - Neue Entwicklungen an Fließgewässern, Hängen und Böschungen, Vienna, Austria, 12.02.2015 - 13.02.2015]

, Ingenieurbiologie. Mitteilungsblatt für die Mitglieder des Vereins für Ingenieurbiologie, 15, 11-14

Philipp Weihs, Heidelinde Trimmel, Florian Dossi, Herbert Formayer , Wolfram Graf, Gerda Holzapfel, Patrick Leitner, Andreas Melcher und Hans Peter Rauch (2014): Untersuchung des Einflusses von Ufervegetation auf die Wassertemperaturen von fließenden Gewässern: Maßnahme gegen den Einfluss des Klimawandels. [Poster]
[8. BIOMET-Tagung, Mensch-Pflanze-Atmosphäre im 21. Jahrhundert., Dresden, Germany, 02.12.2014 - 03.12.2014]

In: Valeri Goldberg und Christian Bernhofer, 8. BIOMET-Tagung Mensch-Pflanze-Atmosphäre im 21. Jahrhundert, Tharandter Klimaprotokolle Band 20, S.131-132.

Trimmel, H., Weihs, P., Formayer, H., Holzapfel, G., Rauch, H.P., Dossi, F., Graf, W., Leitner, P., Melcher, A. (2013): Modeling the energy fluxes of low land rivers including the shading effect of river geometry and riparian vegetation. [Poster]
[14. Klimatag 2013 - Klimawandel, Auswirkungen und Anpassung sowie Vermeidung, Vienna, Austria, 04.04.2013 - 05.04.2013]

In: Climate Change Center Austria, CCCA, Klima und Energiefonds, BOKU, 14. Klimatag, Klimawandel, Auswirkungen und Anpassung sowie Vermeidung

G. Holzapfel, P. Weihs, L. Stockreiter, and E. Hoffmann (2012): Determination of the Annual Shading Potential of Salix Purpurea Coppice using Hemispherical Photographs . [Poster]
[European Geosciences Union EGU General Assembly EGU 2012, Vienna, Austria, 22.04.2012 - 27.04.2012]

, Geophysical Research Abstracts, 14, 7879-7879

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