Estimation of surface net radiation in the boreal forest and northern prairie from shortwave flux measurements

Kaminsky, Keith Z.; Dubayah, R.

doi:10.1029/97jd02314

Cited by 44 publications

(40 citation statements)

References 21 publications

(33 reference statements)

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“…Accurate flux measurements were possible on several days, however, when the wind direction was ideal to sample air from the forest to the north. The measurement of solar radiation, externally calibrated and converted to net radiation (18), was used as one verification of flux quality (16). The closure condition requires that the observed net radiation downward (R n ), less the storage heat flux (S) (19), is equivalent to the observed sensible heat flux upward (SH, heat that can be measured) plus latent heat flux upward (LE, heat that is used to evaporate water).…”

Section: Resultsmentioning

confidence: 99%

Rapid deposition of oxidized biogenic compounds to a temperate forest

Nguyen

Crounse

Teng

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

242

433

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We report fluxes and dry deposition velocities for 16 atmospheric compounds above a southeastern United States forest, including: hydrogen peroxide (H 2 O 2 ), nitric acid (HNO 3 ), hydrogen cyanide (HCN), hydroxymethyl hydroperoxide, peroxyacetic acid, organic hydroxy nitrates, and other multifunctional species derived from the oxidation of isoprene and monoterpenes. The data suggest that dry deposition is the dominant daytime sink for small, saturated oxygenates. Greater than 6 wt %C emitted as isoprene by the forest was returned by dry deposition of its oxidized products. Peroxides account for a large fraction of the oxidant flux, possibly eclipsing ozone in more pristine regions. The measured organic nitrates comprise a sizable portion (15%) of the oxidized nitrogen input into the canopy, with HNO 3 making up the balance. We observe that water-soluble compounds (e.g., strong acids and hydroperoxides) deposit with low surface resistance whereas compounds with moderate solubility (e.g., organic nitrates and hydroxycarbonyls) or poor solubility (e.g., HCN) exhibited reduced uptake at the surface of plants. To first order, the relative deposition velocities of water-soluble compounds are constrained by their molecular diffusivity. From resistance modeling, we infer a substantial emission flux of formic acid at the canopy level (∼1 nmol m −2 ·s −1 ). GEOS−Chem, a widely used atmospheric chemical transport model, currently underestimates dry deposition for most molecules studied in this work. Reconciling GEOS−Chem deposition velocities with observations resulted in up to a 45% decrease in the simulated surface concentration of trace gases.biosphere−atmosphere exchange | isoprene | dry deposition | OVOCs | fluxes

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Section: Resultsmentioning

confidence: 99%

Rapid deposition of oxidized biogenic compounds to a temperate forest

Nguyen

Crounse

Teng

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

242

433

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“…The relationship expressed by Eq. (10), particularly for cloudless skies, is statistically significant (Kaminsky and Dubayah, 1997;Alados et al, 2003). The evidence presented in these studies has contributed to the general acceptance of the use of this model.…”

Section: Proposal Of Preliminary Net Radiation Modelsmentioning

confidence: 97%

Parameterization of net radiation in an arid city of northwestern Mexico

Cueto¹,

Santillán-Soto²,

Rincón³

et al. 2015

Atmósfera

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mosférica (K 0 ) y la emisividad atmosférica (ε atm asfalto, concreto, poliestireno con pintura elastomérica blanca (PPEB), arcilla y césped. Se encontró que para un ciclo de 24 h de medición, el mayor valor promedio de radiación neta fue para el asfalto (146.1 Wm -2 ), y el menor valor promedio para el ). Los valores estimados de albedo varían de acuerdo K 0 y ε atm dependen de las condiciones atmosféricas prevalentes. A partir de las mediciones se propusieron modelos estadísticos preliminares de la radiación neta en función de la determinación superiores a 0.97. Se analizan las probables implicaciones de los resultados encontrados en el medio urbanizado. ABSTRACT paper attempts to quantify this balance over different surface types in an arid city of northwest Mexico over several days in August 2011. The albedo of each surface type, as well as local atmospheric properties such as the atmospheric clearness index (K 0 ) and atmospheric emissivity (ε atm ), were estimated. The surfaces on which measurements were performed were asphalt, concrete, polystyrene painted with white elastomeric paint (PWEP), clay, and grass. It was found that, for a 24-h cycle of measurement, the highest average value of net radiation was for asphalt ), and the lowest average value was for PWEP ). Estimates of albedo values vary depending on the surface, whereas K 0 and ε atm are dependent on prevailing atmospheric conditions. From these measurements, preliminary statistical models of net radiation as a function determination were higher than 0.97. We discuss the likely implications of the results found for the urban planning of the city.

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“…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: 99%

“…For example, MODIS albedo is known to be biased in snow or partially snow covered situations [61]. Although, daily net-radiation is not very sensitive to albedo [1], over seasonal time scale variations in albedo in higher latitudes can influence net-radiation through its effect on outgoing shortwave radiation [55]. To calculate outgoing longwave radiation we used prescribed emissivity in band 31 and 32 from the MOD11 product and used a simple formulation to estimate broadband emissivity.…”

Section: Reliability and Accuracy Of Modis Net-radiationmentioning

confidence: 99%

Global Surface Net-Radiation at 5 km from MODIS Terra

et al. 2016

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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.

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Estimation of surface net radiation in the boreal forest and northern prairie from shortwave flux measurements

Cited by 44 publications

References 21 publications

Rapid deposition of oxidized biogenic compounds to a temperate forest

Rapid deposition of oxidized biogenic compounds to a temperate forest

Parameterization of net radiation in an arid city of northwestern Mexico

Global Surface Net-Radiation at 5 km from MODIS Terra

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