LAND BIOGEOPHYSICAL VARIABLES OF THE MEDITERRANEAN BASIN TO WHAT

BIOGEOPHYSICAL AND SOCIAL VULNERABILITY INDICATORS COASTAL CASE STUDIES INFORMATION
Land Biogeophysical Variables of the Mediterranean Basin to What

Vertically aligned multi walled carbon nanotubes and horizontally suspended single walled carbon nanotubes grown by CCVD

Land biogeophysical variables of the Mediterranean basin: to what extent can ERA-I be used to drive land surface models ?

Camille Szczypta, Jean-Christophe Calvet⁽¹⁾

⁽¹⁾ CNRM-GAME, Météo-France, CNRS, Toulouse, France

The HYMEX TTM3b action is related to hindcast runs over the Mediterranean basin. The land component of this action will consist in building climatologies of land surface variables (e.g. soil moisture, evapotranspiration, optionally LAI and carbon fluxes), and (optionally) river flow, over the whole Mediterranean basin. This modelling exercise has to be coupled with the use of in situ and satellite data for verification. A number of biogeophysical variables (soil moisture, leaf area index) can be observed from space and simulated by land surface models. CNRM and ENEA (in collaboration with IPSL -LMD and LSCE-) will build climatologies of land biogeophysical variables, using land surface models forced by atmospheric reanalyses, and will compare the model climatology with available satellite and in situ observations. The ECMWF ERA-Interim global analysis will be used, together with a dynamical downscaling over specific areas.

In a first stage, CNRM has performed an evaluation of ERA-Interim over France, based on the high resolution (8km) SAFRAN atmospheric reanalysis. The ERA-Interim precipitation, incoming solar radiation (ISR), air temperature, air humidity, and wind speed, were evaluated. Also, interpolated in situ ISR observations were used in order to consolidate the evaluation of this variable.

The daily precipitation estimates produced by ERA-Interim over France correlate very well with SAFRAN. However, the values are underestimated by 26%. A GPCP-corrected version of ERA-Interim is less biased (10-15%). The ERA-Interim estimates of ISR correlate very well with SAFRAN and with the ISR in situ observations on a daily basis. Whereas SAFRAN underestimates the ISR by 6-8 Wm-2, ERA-Interim overestimates the ISR by 9-10 Wm-2. Actions are needed in order to reduce these biases and the impact of using ERA-Interim in land surface models has to be assessed.

Corresponding author: Jean-Christophe Calvet, [email protected]

Preference: oral

Tags: variables, mediterranean, biogeophysical, basin