Search results for "Sensible"

Estimating high resolution evapotranspiration from disaggregated thermal images

2016

Abstract Accurate evapotranspiration (ET) estimations based on surface energy balance from remote sensing require information in the thermal infrared (TIR) domain, normally provided with an insufficient spatial resolution. In order to estimate ET in heterogeneous agricultural areas, we inspect in this paper the use of disaggregation techniques applied to two different sensors, such as MODIS (daily revisit cycle and 1 km spatial resolution in the TIR domain) and Spot 5 (5 days revisit cycle and 10 m spatial resolution in the VNIR bands but no TIR band). Spot 5 images were used as a proxy for upcoming Sentinel-2. The Simplified Two-Source Energy Balance (STSEB) model was used for the estimati…

2016

Gianluca Tramontana was supported by the GEOCARBON EU FP7 project (GA 283080). Dario Papale, Martin Jung and Markus Reichstein acknowledge funding from the EU FP7 project GEOCARBON (grant agreement no. 283080) and the EU H2020 BACI project (grant agreement no. 640176). Gustau Camps-Valls wants to acknowledge the support by an ERC Consolidator Grant with grant agreement 647423 (SEDAL). Kazuhito Ichii was supported by Environment Research and Technology Development Funds (2-1401) from the Ministry of the Environment of Japan and the JAXA Global Change Observation Mission (GCOM) project (no. 115). Christopher R. Schwalm was supported by National Aeronautics and Space Administration (NASA) gran…

Aestivation motifs explain hypertension and muscle mass loss in mice with psoriatic skin barrier defect

2021

Aim Recent evidence suggests that arterial hypertension could be alternatively explained as a physiological adaptation response to water shortage, termed aestivation, which relies on complex multi-organ metabolic adjustments to prevent dehydration. Here, we tested the hypothesis that chronic water loss across diseased skin leads to similar adaptive water conservation responses as observed in experimental renal failure or high salt diet. Methods We studied mice with keratinocyte-specific overexpression of IL-17A which develop severe psoriasis-like skin disease. We measured transepidermal water loss and solute and water excretion in the urine. We quantified glomerular filtration rate (GFR) by…

Modeling of biomass smoke injection into the lower stratosphere by a large forest fire (Part II): Sensitivity studies

2006

Abstract. The Chisholm forest fire that burned in Alberta, Canada, in May 2001 resulted in injection of substantial amounts of smoke into the lower stratosphere. We used the cloud-resolving plume model ATHAM (Active Tracer High resolution Atmospheric Model) to investigate the importance of different contributing factors to the severe intensification of the convection induced by the Chisholm fire and the subsequent injection of biomass smoke into the lower stratosphere. The simulations show strong sensitivity of the pyro-convection to background meteorology. This explains the observed coincidence of the convective blow-up of the fire plume and the passage of a synoptic cold front. Furthermor…

The impact of in-canopy wind profile formulations on heat flux estimation in an open orchard using the remote sensing-based two-source model

2010

Abstract. For open orchard and vineyard canopies containing significant fractions of exposed soil (>50%), typical of Mediterranean agricultural regions, the energy balance of the vegetation elements is strongly influenced by heat exchange with the bare soil/substrate. For these agricultural systems a "two-source" approach, where radiation and turbulent exchange between the soil and canopy elements are explicitly modelled, appears to be the only suitable methodology for reliably assessing energy fluxes. In strongly clumped canopies, the effective wind speed profile inside and below the canopy layer can strongly influence the partitioning of energy fluxes between the soil and vegetation co…

Applications of a remote sensing-based two-source energy balance algorithm for mapping surface fluxes without in situ air temperature observations

2012

Abstract The two-source energy balance (TSEB) model uses remotely sensed maps of land–surface temperature (LST) along with local air temperature estimates at a nominal blending height to model heat and water fluxes across a landscape, partitioned between dual sources of canopy and soil. For operational implementation of TSEB, however, it is often difficult to obtain representative air temperature data that are compatible with the LST retrievals, which may themselves have residual errors due to atmospheric and emissivity corrections. To address this issue, two different strategies in applying the TSEB model without requiring local air temperature data were tested over a typical Mediterranean…

Intercomparison and analyses of the climatology of the West African Monsoon in the West African Monsoon Modeling and Evaluation project (WAMME) first…

2010

International audience; This paper briefly presents the West African Monsoon (WAM) Modeling and Evaluation Project (WAMME) and evaluates WAMME general circulation models' (GCM) performances in simulating variability of WAM precipitation, surface temperature, and major circulation features at seasonal and intraseasonal scales in the first WAMME experiment. The analyses indicate that models with specified sea surface temperature generally have reasonable simulations of the pattern of spatial distribution of WAM seasonal mean precipitation and surface temperature as well as the averaged zonal wind in latitude-height cross-section and low level circulation. But there are large differences among mo…

Radiative surface temperature and convective flux calculation over crop canopies

1988

The analysis presented in this paper aims at a better understanding of the potential role of radiative temperature, as measured by a radiometer over crops, in sensible heat flux calculation. Defining radiative temperature as the mean temperature of the surfaces viewed by the radiometer (leaves and soil surface) and assuming that an Ohm's law type formula can be used to express sensible heat flux as a function of the difference between air temperature and radiative temperature, the aerodynamic resistance which divides this temperature difference has been analytically defined. The parameters which appear in the resistance expression depend essentially on wind velocity and canopy structure but…

Sensitivity of the atmospheric temperature profile to the aerosol absorption in the presence of dust

2014

Abstract Radiative transfer simulations in the shortwave (SW) and longwave (LW) spectral regions have been carried out to investigate the time evolution of the atmospheric heating/cooling rates and their influence on the temperature profiles under different vertical distributions of the aerosol absorption. The case study is based on measurements made at Rome, Italy, on 20 June 2007, when a dust layer was present above the urban boundary layer (BL) and the column aerosol optical depth at 550 nm was about 0.37. Column-integrated aerosol optical depth and single scattering albedo, as well as vertical profiles of aerosol extinction and meteorological variables have been derived from observation…

Monitoring daily evapotranspiration at a regional scale from Landsat-TM and ETM+ data: Application to the Basilicata region

2008

Summary The increasing interest of hydrological, climatic and meteorological models in the different components of the surface energy balance has encouraged the development of operational methods for estimating surface energy fluxes at a regional scale. In this paper, a sequence of three high-resolution satellite-based surface energy fluxes images are analyzed over an extensive area with a large variety of land uses. Two images from Landsat 7-ETM+ (1999, 2002) and one from Landsat 5-TM (2004) are collected covering the whole Basilicata region (Southern Italy). A Simplified version of a Two-Source Energy Balance (STSEB) model is used to retrieve the surface sensible heat flux. A balance betw…