Relationship between net radiation and solar radiation for semi-arid shrub-land

Alados, I.; Foyo-Moreno, I.; Olmo, F.J.; Alados-Arboledas, L.

doi:10.1016/s0168-1923(03)00038-8

Cited by 89 publications

(57 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Observations from the FLUXNET and SURFRAD stations showed that of the four components, incoming shortwave radiation was most strongly correlated with net-radiation across all six climate types, and was the main driver of seasonal variations in instantaneous net-radiation [1,55,56]. Mean R 2 (across site) between incoming shortwave radiation and net-radiation was 0.89, 0.86, 0.91, 0.91, 0.82, and 0.80 in boreal, temperate-continental, temperate, Mediterranean, semi-arid, and tropical climates, respectively.…”

Section: Reliability and Accuracy Of Modis Net-radiationmentioning

confidence: 98%

See 1 more Smart Citation

Global Surface Net-Radiation at 5 km from MODIS Terra

et al. 2016

View full text Add to dashboard Cite

Reliable and fine resolution estimates of surface net-radiation are required for estimating latent and sensible heat fluxes between the land surface and the atmosphere. However, currently, fine resolution estimates of net-radiation are not available and consequently it is challenging to develop multi-year estimates of evapotranspiration at scales that can capture land surface heterogeneity and are relevant for policy and decision-making. We developed and evaluated a global net-radiation product at 5 km and 8-day resolution by combining mutually consistent atmosphere and land data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board Terra. Comparison with net-radiation measurements from 154 globally distributed sites (414 site-years) from the FLUXNET and Surface Radiation budget network (SURFRAD) showed that the net-radiation product agreed well with measurements across seasons and climate types in the extratropics (Wilmott's index ranged from 0.74 for boreal to 0.63 for Mediterranean sites). Mean absolute deviation between the MODIS and measured net-radiation ranged from 38.0 ± 1.8 W·m −2 in boreal to 72.0 ± 4.1 W·m −2 in the tropical climates. The mean bias was small and constituted only 11%, 0.7%, 8.4%, 4.2%, 13.3%, and 5.4% of the mean absolute error in daytime net-radiation in boreal, Mediterranean, temperate-continental, temperate, semi-arid, and tropical climate, respectively. To assess the accuracy of the broader spatiotemporal patterns, we upscaled error-quantified MODIS net-radiation and compared it with the net-radiation estimates from the coarse spatial (1 • × 1 • ) but high temporal resolution gridded net-radiation product from the Clouds and Earth's Radiant Energy System (CERES). Our estimates agreed closely with the net-radiation estimates from the CERES. Difference between the two was less than 10 W·m −2 in 94% of the total land area. MODIS net-radiation product will be a valuable resource for the science community studying turbulent fluxes and energy budget at the Earth's surface.

show abstract

Section: Reliability and Accuracy Of Modis Net-radiationmentioning

confidence: 98%

“…Surface net-radiation is a critical component of the global water and energy cycle [1]. It couples the land surface to the lower atmosphere and exerts a dominant control on the terrestrial hydrological cycle [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Global Surface Net-Radiation at 5 km from MODIS Terra

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The coefficients of such relationship are valid only for given localities, season and specific coverage (Alados et al, 2003). Conversely, semi-empirical models are based on R n,s and R n,l estimates and have been an important alternative to compute R n when it is not measured (Fontana et al, 1991;Ortega-Farías et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Observed and modelled solar radiation components in sugarcane crop grown under tropical conditions

Santos¹,

Souza²,

Lyra³

et al. 2017

International Agrophysics

View full text Add to dashboard Cite

A b s t r a c t. The net radiation over vegetated surfaces is one of the major input variables in many models of soil evaporation, evapotranspiration as well as leaf wetness duration. In the literature there are relatively few studies on net radiation over sugarcane crop in tropical climates. The main objective of the present study was to assess the solar radiation components measured and modelled for two crop stages of a sugarcane crop in the region of Rio Largo, Alagoas, North-eastern Brazil. The measurements of the radiation components were made with a net radiometer during the dry and rainy seasons and two models were used to estimate net radiation: the Ortega-Farias model and the Monteith and Unsworth model. The highest values of net radiation were observed at the crop development stage, due mainly to the high indices of incoming solar radiation. The daily average albedos of sugarcane at the crop development and mid-season stages were 0.16 and 0.20, respectively. Both models showed a better fit for the crop development stage than for the mid-season stage. When they were inter-compared, Monteith and Unsworth model was more efficient than Ortega-Farias model, despite the dispersion of their simulated radiation components which was similar.

show abstract

“…Initially, Rn was estimated only from the incoming solar radiation, Rsi [12,13]. Then surface albedo was incorporated with claims that the fitting accuracy of models could be improved [14], but later studies found that the improvement brought mixed results [15]. Later, other models were developed by incorporating more meteorological parameters (i.e., air temperature, cloud cover) and other variables (i.e., relative Earth-Sun distance, land covers represented by the Normalized Difference Vegetation Index (NDVI)) and these models were evaluated by many studies [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Surface Daytime Net Radiation Estimation Using Artificial Neural Networks

et al. 2014

View full text Add to dashboard Cite

Net all-wave surface radiation (Rn) is one of the most important fundamental parameters in various applications. However, conventional Rn measurements are difficult to collect because of the high cost and ongoing maintenance of recording instruments. Therefore, various empirical Rn estimation models have been developed. This study presents the results of two artificial neural network (ANN) models (general regression neural networks (GRNN) and Neuroet) to estimate Rn globally from multi-source data, including remotely sensed products, surface measurements, and meteorological reanalysis products. Rn estimates provided by the two ANNs were tested against in-situ radiation measurements obtained from 251 global sites between 1991-2010 both in global mode (all data were used to fit the models) and in conditional mode (the data were divided into four subsets and the models were fitted separately). Based on the results obtained from extensive experiments, it has been proved that the two ANNs were superior to linear-based empirical models in both global and conditional modes and that the GRNN performed better and was more stable than Neuroet. The GRNN estimates had a determination coefficient (R

show abstract

Relationship between net radiation and solar radiation for semi-arid shrub-land

Cited by 89 publications

References 14 publications

Global Surface Net-Radiation at 5 km from MODIS Terra

Global Surface Net-Radiation at 5 km from MODIS Terra

Observed and modelled solar radiation components in sugarcane crop grown under tropical conditions

Surface Daytime Net Radiation Estimation Using Artificial Neural Networks

Contact Info

Product

Resources

About