| Title | Estimation of Evapotranspiration by use of Remote Sensing techniques |
| Abstract | The increasing concentration of CO2 and other radiative active
trace gases in the atmosphere is causing tropospheric
temperatures to rise. Changes in other climatic features
such as precipitation, cloudiness, humidity, and windiness
are likely to follow changes in temperature. Such changes
could have deep implications for hydrologic processes in general
and for water availability to sustain both rain-fed and
irrigated agriculture, in particular.
Evapotranspiration (ET) is the compound term describing
the physical processes of water transfer into the atmosphere
by evaporation from soil and transpiration through vegetation;
ET constitutes an important component of hydrological
balance particularly in semi-arid and sub-humid climates.
Evapotranspiration is determined by various mathematical
models using climatic factors such as temperature, radiation,
humidity, and wind speed, while its direct measurement is
seldom available in experimental fields.
A relatively new technology using on remote sensing to retrieve
land surface parameters such as surface temperature,
albedo and vegetation indices - which are indispensable to remotely
sensed ET models - is adopted here to map regional,
meso- and macro-scale patterns of ET at the earth's surface
in a globally consistent and economically feasible manner.
The aim of our research is to assess a technique to retrieve
ET maps from remote sensing images by the combination of
two different procedures. The first one, known as triangle
method, computes the evapotranspiration fraction (EF) de-
fined as the ratio LE/Rn, where Rn is the net radiation at
the surface and LE is the latent heat flux. LE is directly proportional
to ET. In order to retrieve LE, and consequently
the surface evapotranspiration, a second procedure computes
the net radiation of the investigated area. Therefore, by inversion,
it is possible to obtain an estimate of the ET.
The validation of these variables, the net radiation and of
the evapotranspiration derived from MODIS data, has been
undertaken on the Capitanata area, Southern Italy, by comparison
of model results with in-situ measurements provided
by the Consorzio per la Bonifica della Capitanata di Foggia. |
| Source | IMCM - 3rd Meeting on Meteorology and Climatology of the Mediterranean, Nova Yardinia, Castellaneta Ma, 2011Tethys (Cornellà de Llobregat) |
| Keywords | - |
| Journal | Tethys (Cornellà de Llobregat) |
| Editor | ACAM., Cornellà de Llobregat, [Barcelona], Spagna |
| Year | 2011 |
| Type | Contributo in atti di convegno |
| Authors | Matarrese R., Portoghese I., Vurro M., Soldo P. |
| Text | 89838 2011 Estimation of Evapotranspiration by use of Remote Sensing techniques Matarrese R., Portoghese I., Vurro M., Soldo P. 1CNR IRSA, Bari, Italy 2Consorzio per la Bonifica della Capitanata, Foggia, Italy The increasing concentration of CO2 and other radiative active trace gases in the atmosphere is causing tropospheric temperatures to rise. Changes in other climatic features such as precipitation, cloudiness, humidity, and windiness are likely to follow changes in temperature. Such changes could have deep implications for hydrologic processes in general and for water availability to sustain both rain fed and irrigated agriculture, in particular. Evapotranspiration ET is the compound term describing the physical processes of water transfer into the atmosphere by evaporation from soil and transpiration through vegetation; ET constitutes an important component of hydrological balance particularly in semi arid and sub humid climates. Evapotranspiration is determined by various mathematical models using climatic factors such as temperature, radiation, humidity, and wind speed, while its direct measurement is seldom available in experimental fields. A relatively new technology using on remote sensing to retrieve land surface parameters such as surface temperature, albedo and vegetation indices which are indispensable to remotely sensed ET models is adopted here to map regional, meso and macro scale patterns of ET at the earth s surface in a globally consistent and economically feasible manner. The aim of our research is to assess a technique to retrieve ET maps from remote sensing images by the combination of two different procedures. The first one, known as triangle method, computes the evapotranspiration fraction EF de fined as the ratio LE/Rn, where Rn is the net radiation at the surface and LE is the latent heat flux. LE is directly proportional to ET. In order to retrieve LE, and consequently the surface evapotranspiration, a second procedure computes the net radiation of the investigated area. Therefore, by inversion, it is possible to obtain an estimate of the ET. The validation of these variables, the net radiation and of the evapotranspiration derived from MODIS data, has been undertaken on the Capitanata area, Southern Italy, by comparison of model results with in situ measurements provided by the Consorzio per la Bonifica della Capitanata di Foggia. Published version http //www.tethys.cat/IMMCM/4Banyuls/ficheros/AbstractsBook_IMMCM_2011.pdf IMCM 3rd Meeting on Meteorology and Climatology of the Mediterranean Nova Yardinia, Castellaneta Ma 2011 Internazionale Contributo Contributo in atti di convegno ACAM. 1139 3394 Tethys Cornella de Llobregat Tethys Cornella de Llobregat Tethys Cornella de Llobregat ivan.portoghese PORTOGHESE IVAN raffaella.matarrese MATARRESE RAFFAELLA michele.vurro VURRO MICHELE TA.P02.031.001 Impatto dei cambiamenti climatici sulla gestione delle risorse idriche |
