Search Results

You are looking at 71 - 80 of 9,529 items for :

  • Infrared radiation x
  • All content x
Clear All
Changyong Cao, Hui Xu, Jerry Sullivan, Larry McMillin, Pubu Ciren, and Yu-Tai Hou

1. Introduction The High-Resolution Infrared Radiation Sounder (HIRS) was initially designed for weather applications, with only a moderate requirement for calibration accuracy. However, as more than 25 yr of HIRS data have been accumulated, scientists are increasingly interested in using this data for climate studies where high calibration accuracy is essential. For example, HIRS data have been used for the long-term global statistics of high cloud ( Wylie and Menzel 1999 ) and for evaluating

Full access
Shaima L. Nasiri and Brian H. Kahn

determination is also a necessary step in the retrieval of cloud particle size, optical thickness, and water path. Much progress has been made in recent years with cloud phase assessment using near-infrared measurements of reflected solar radiation ( Pilewskie and Twomey 1987 ; Riedi et al. 2000 ; Knap et al. 2002 ; Platnick et al. 2003 ; Chylek et al. 2006 ; Pavolonis et al. 2005 ), while others have combined near-infrared reflectances with mid-IR brightness temperatures (BTs; Kokhanovsky et al. 2006

Full access
Daniel K. Zhou, William L. Smith Sr., Xu Liu, Allen M. Larar, Stephen A. Mango, and Hung-Lung Huang

1. Introduction Nadir observations from a spacecraft- or an aircraft-flown infrared instrument can be used to infer the atmospheric temperature, moisture, and concentration of other chemical species using radiative transfer equation inversion techniques. The retrievals of atmospheric state, temperature, and moisture profiles obtained from infrared radiometric measurements will contain intolerable error near and below the cloud level if the cloud radiation and the attenuation of infrared

Full access
K. Franklin Evans

1. Introduction Variational assimilation of visible and infrared radiances by numerical models in cloudy skies requires forward and adjoint radiative transfer models capable of handling scattering. When cloud properties are the target of the assimilation, visible and near-infrared satellite radiances should be considered because reflected solar radiation provides important information about cloud water path and particle size (e.g., Twomey and Cocks 1982 ). Due to heavy computational costs and

Full access
Kevin J. Garrett, Ping Yang, Shaima L. Nasiri, Christopher R. Yost, and Bryan A. Baum

1. Introduction Ice clouds play an important role in regulating the earth’s radiation budget through their reflection of solar radiation and trapping of the earth’s outgoing infrared (IR) radiation. Determination of the net cloud radiative forcing of these clouds requires a global, diurnal climatology, which can most readily be achieved using satellite observation. At present, the parameterization of ice cloud properties is a primary cause of discrepancy in cloud radiative forcings calculated

Full access
Quanhua Liu and Fuzhong Weng

ordinate radiative transfer model ( Spurr et al. 2001 ). In the following, ADA is derived and the intercomparison with other models is carried out. 2. Radiative transfer solver Using the discrete ordinate form from Weng and Liu (2003) , the nonpolarized radiative transfer equation in the infrared and microwave ranges can be written as where μ i (note μ −i = − μ i ) and w i are Gaussian quadrature points and weights, respectively. Here μ i and μ −i represent the cosine of the viewing zenith

Full access
Arnon Karnieli, Nurit Agam, Rachel T. Pinker, Martha Anderson, Marc L. Imhoff, Garik G. Gutman, Natalya Panov, and Alexander Goldberg

. Remote Sens. , 28 , 4823 – 4840 . Ottle , C. , and D. Vidalmadjar , 1994 : Assimilation of soil moisture inferred from infrared remote sensing in a hydrological model over the HAPEX-Mobilhy region. J. Hydrol. , 158 , 241 – 264 . Pinker , R. T. , and J. A. Ewing , 1985 : Modeling surface solar radiation: Model formulation and validation. J. Climate Appl. Meteor. , 24 , 389 – 401 . Pinker , R. T. , and I. Laszlo , 1992 : Modeling surface solar irradiance for satellite

Full access
T. Koyama, T. Vukicevic, M. Sengupta, T. Vonder Haar, and A. S. Jones

radiative transfer (RT) models depending on the radiation source. The two RT models used are the spherical harmonic discrete ordinate method (SHDOM; Evans 1998 ) for visible wavelengths and a delta-Eddington two-stream approach (e.g., Deeter and Evans 1998 ) for the infrared. It should be noted that both the models account for multiple scattering. Compared with other RT models available for visible computations, SHDOM is more accurate and can accommodate complicated scattering phase functions within

Full access
Ulrich Löhnert, D. D. Turner, and S. Crewell

temperature and humidity with a high temporal resolution but suffer some drawbacks in vertical resolution and accuracy. This paper compares the performance of ground-based temperature and humidity profiling methods in two different spectral regions: microwave and infrared. Using identical retrieval approaches, we will address the following questions: What are the respective merits of microwave and infrared ground-based temperature and humidity profiling, and what can be gained from a combination of both

Full access
Davide Capacci and Federico Porcù

1. Introduction The quantitative description of precipitation patterns from spaceborne passive sensors is a challenging task in meteorological remote sensing, given the elusive relationship between precipitation characteristics and the radiation detected by satellite sensors. Precipitation estimates at high temporal and spatial resolution are operationally used within forecasting systems in meteorological and hydrological services, with efforts underway to use them in assimilation chains

Full access