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Mark A. Miller, Virendra P. Ghate, and Robert K. Zahn

season rainfall. Like many other under-sampled regions, the Sahel suffers from a scarcity of reliable surface observations and a heavy reliance upon satellite radiation measurements to benchmark GCM performance. Even in data-rich areas the cross-atmosphere radiation flux divergence and its controls are rarely measured with the temporal resolution, completeness, and accuracy required to determine how the controls and the radiative fluxes interact. This study overcomes this obstacle using nearly

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Norman G. Loeb, Ping Yang, Fred G. Rose, Gang Hong, Sunny Sun-Mack, Patrick Minnis, Seiji Kato, Seung-Hee Ham, William L. Smith Jr., Souichiro Hioki, and Guanglin Tang

passive visible/infrared imager measurements, assumptions about the bulk single-scattering properties of ice clouds are necessary in order to retrieve ice cloud optical properties (e.g., optical depth) from imager radiances and to compute broadband radiative fluxes. Here we show that satellite-derived surface radiative fluxes determined using a consistent ice particle model assumption in the cloud property retrievals and forward radiative transfer model calculation are far less sensitive to the

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Satoshi Sakai, Aya Ito, Kazuhiro Umetani, Isao Iizawa, and Masanori Onishi

1. Introduction The earth’s longwave radiative flux is a crucial parameter in determining the energy balance at the surface, and is of great importance not only for the global climate but also for the local thermal environment. However, measuring longwave radiative fluxes is difficult compared with other parameters such as air temperature because it requires expensive equipment and an open sky for operation. In particular, the requirement of an open sky can obstruct the observation of longwave

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M. Ibáñez, P. J. Pérez, J. I. Rosell, and F. Castellví

Introduction After two decades of research into the determination of evapotranspiration ( λE ) from the radiative temperature ( T s ), applying one- and two-level models in partial or complete canopies, the scientific community realizes that it is not possible to model the complicated physiological and physical processes involved in the phenomenon with models based on a few soil, canopy, and atmospheric parameters. However, the need for knowledge about the latent heat flux at a regional scale

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J. P. Funk

388JOURNAL OF METEOROLOGY\?OLUME 18A NUMERICAL METHOD FOR THE COMPUTATION OF THE RADIATIVE FLUX DIVERGENCE NEAR THE GROUND J. P. Funk Coinmonwealth Scientific and Industrial Research Organization, Aspendale, Australia(Original nianuscript received 22 August 1960; revised manuscript received 15 November 1961).ABSTRACTA numerical method for the computation of radiative flux divergence is given, which is particularly suitedfor micrometeorological use. By avoiding derivatives of

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M. Ibañez, P. J. Pérez, V. Caselles, and F. Castellvi

speed, atmospheric stability, and surface roughness. One of the most serious drawbacks of the method lies in aerodynamic resistance. There are different approaches to reduce the error caused by replacement of aerodynamic surface temperature with the surface radiative temperature in the bulk aerodynamic formulation to estimate the sensible heat flux. Aerodynamic resistance, when the radiative temperature is considered, needs 1) a new stability function ( Brutsaert 1992 ), 2) replacement of

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Frank L. Martin and Wallace C. Palmer

780 JOURNAL OF APPLIED METEOROLOGY Vo~.u~sE3Statistical Estimates of Computed Water-Vapor Radiative Flux from Clear Skies at an Oceanic Location FRANK L. ~IA~RTIN$U. S. Na~al Postgraduats School, Monterey, Calif. A~r~ Wa.~.Acv. C. Pazarg2, LCDR, USNFled Numerical Weather Facility, Monterey, Calif.(Manuscript reviewed 8 May 1964, in revised form 27 July 1964) Based upon four years of

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Xiping Zeng, Wei-Kuo Tao, Minghua Zhang, Arthur Y. Hou, Shaocheng Xie, Stephen Lang, Xiaowen Li, David O’C. Starr, Xiaofan Li, and Joanne Simpson

between the aerosol particle and cloud (ice) particle populations, and the second is the connection between precipitation formation in the middle troposphere and the radiative roles of mixed-phase clouds. In this study, long-term cloud-resolving model (CRM) simulations are utilized to bridge the two gaps and further study the indirect effect of ice nuclei (IN; a form of aerosols) on radiative forcing or the net radiative flux at the top of the atmosphere (TOA). a. CRM simulations CRMs, when

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Johannes Schmetz

1122 JOURNAL OF THE ATMOSPHERIC SCIENCES VOL. 50, No. 8Relationship between Solar Net Radiative Fluxes at the Top of the Atmosphere and at the Surface JOHANNES SCHMETZEuropean Space Agency, European Space Operations Centre, Darmstadt, Germany(Manuscript received 20 February 1992, in final form 16 June 1992)ABSTRACT Previous work has discussed the existence of a linear relmionship between the net solar

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P. M. Gabriel and K. F. Evans

a means of incoq~orating horizontal cloud inhomogeneity in radiative transfercalculations is widespread in the atmospheric science community. This study addresses some issues pertainingto the use of cloud fraction by performing radiative uansfer in inhomogeneous two-dimansional media. Twoapproximation techniques are developed to solve the equation of Iransfer for the spatial averages of diffuse flux.The first is based on a first-order closure technique that leads to a one-dimensional equation of

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