Author: Rand E. FeindPublisher:
ISBN:
Category : Carbon dioxide
Languages : en
Pages : 178
Book Description
Retrieval of Cloud Properties from the Airborne Visible/infrared Imaging Spectrometer (AVIRIS) and the Thermal Infrared Multispectral Scanner(TIMS)
Author: Rand E. FeindPublisher:
ISBN:
Category : Carbon dioxide
Languages : en
Pages : 178
Book Description
Masters Theses in the Pure and Applied Sciences
Author: W. H. ShaferPublisher: Springer Science & Business Media
ISBN: 9780306447112
Category : Education
Languages : en
Pages : 410
Book Description
Volume 37 (thesis year 1992) reports a total of 12,549 thesis titles from 25 Canadian and 153 US universities (theses submitted in previous years but only now reported are indicated by the thesis year shown in parenthesis). The organization, like that of past years, consists of thesis titles arrange
Scientific and Technical Aerospace Reports
Author: Scientific and Technical Aerospace Reports
Author: An Analysis of Cloud Property Retrieval Using Infrared Sounder Data
Author: Bruce Anthony WielickiPublisher:
ISBN:
Category : Clouds
Languages : en
Pages : 288
Book Description
International Aerospace Abstracts
Author: Use of Airs and Modis Thermal Infrared Channels to Retrieve Ice Cloud Properties
Author: Christopher Rogers YostPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
In this study, we use thermal infrared channels to retrieve the optical thickness and effective particle radius of ice clouds. A physical model is used in conjunction with Atmospheric Infrared Sounder (AIRS) temperature and water vapor profiles to simulate the top-of-atmosphere (TOA) brightness temperatures (BTs) observed by the Moderate Resolution Imaging Spectroradiometer (MODIS) for channels located at 8.5, 11.0, and 12.0 [mu] (1176, 909, and 833 cm−1). The model is initially validated by comparing simulated clear-sky BTs to MODIS-observed clear-sky BTs. We also investigate the effect of introducing a +3 [kappa] bias in the temperature profile, a +3 [kappa] bias in the surface temperature, and a +20% bias in the water vapor profile in order to test the sensitivity of the model to these inputs. For clear-sky cases, the simulated TOA BTs agree with MODIS to within 2-3 [kappa]. The model is then extended to simulate thermal infrared BTs for cloudy skies, and we infer the optical thickness and effective radius of ice clouds by matching MODIS-observed BTs to calculations. The optical thickness retrieval is reasonably consistent with the MODIS Collection 5 operational retrieval for optically thin clouds but tends to retrieve smaller particle sizes than MODIS.
Global Cloud Properties on Venus from Orbital Infrared Spectroscopy
Author: Joanna K. BarstowPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Global Cloud Properties on Venus from Orbital Infrared Spectroscopy This thesis describes the derivation of Venusian global cloud properties from in- frared remote sensing data obtained by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on the European Space Agency Venus Express satellite. A computationally-efficient retrieval method is designed to exploit the dataset, which provides coverage of the entire nightside southern hemisphere of Venus. Spatially- resolved near-infrared spectra have been used to derive improved models of the vertical structure and global distribution of cloud properties in the southern hemi- sphere. Wavelengths within transparency windows in the 1.0-2.6 J.Lm range covered by VIRTIS are sensitive on the nightside to absorption by the lower and middle sul- phuric acid cloud layers, which are back-lit by thermally-emitted radiation from the hot lower atmosphere (Taylor et al. 1997). The cloud model used to interpret the spectra builds on work by Crisp (1986), Pollack et al. (1993) and Grinspoon et al. (1993). Retrieved parameters are the acid concentration in the cloud droplets, the average size of the particles in the lower cloud and the altitude of the cloud base in the model. Values are estimated initially using wavelength pairs selected for their unique sensitivity to each parameter, and then validated using model spectra generated using the NEMESIS radiative transfer and retrieval code (Irwin et al. 2008) as developed for Venus (Tsang et al. 2008a). The spatial variation of sulphuric acid concentration in the cloud particles is esti- mated; the concentration is found to be higher in regions of optically thick cloud. The retrieved cloud base altitude varies with latitude, reaching a maximum height near -500 before falling by several km towards the pole. An increase in average particle size near the pole (Wilson et al. 2008) and latitudinally-variable CO abun- dance at 35-40 km altitude (Tsang et al. 2008) are both confirmed. A decrease in tropospheric H20 abundance at high latitudes is observed, and provides evidence for strong downwelling between ±60 and ±75° latitude, which marks the poleward extent of the Hadley cell circulation. Long-term secular change is also observed over a period of two Earth years. The measurements presented here provide a reference dataset for microphysical and dynamical modelling of the cloud deck, and the role of the cloud as a dynamical and chemical tracer means that such observations aid understanding of the Venusian atmosphere.
Study of Cloud Properties from Single-scattering, Radiative Forcing, and Retrieval Perspectives
Author: Yong-Keun LeePublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
This dissertation reports on three different yet related topics in light scattering computation, radiative transfer simulation, and remote sensing implementation, regarding the cloud properties and the retrieval of cloud properties from satellite-based infrared radiometric measurements. First, the errors associated with the use of circular cylinders as surrogates for hexagonal columns in computing the optical properties of pristine ice crystals at infrared (8-12 [micron]) wavelengths are investigated. It is found that the differences between the results for circular cylinders and hexagonal columns are on the order of a few percent at infrared wavelengths. Second, investigated in this dissertation are the outgoing broadband longwave and window channel radiances at the top-of-atmosphere under clear-sky conditions on the basis of the data acquired by the Cloud and the Earth's Radiant Energy System (CERES) instrument onboard the NASA Terra satellite platform. Based on the comparison of the observed broadband radiances with those obtained from rigorous radiative transfer simulations, it is found that the theoretical results tend to be larger than their measured counterparts. Extensive sensitivity studies regarding the uncertainties of various parameters were carried out. Within the considered uncertainties of various factors, the computed radiances are still larger than the observed radiances if thin cirrus clouds are excluded. Thus, a potential cause for the differences could be associated with the presence of thin cirrus clouds whose visible optical thickness is smaller than approximately 0.3. Third, presented in this dissertation is an illustration of the application of hyperspectral infrared channel observations to the retrieval of the cloud properties. Specifically, the hyperspectral measurements acquired from the Atmospheric Infrared Sounder (AIRS) aboard the NASA Aqua platform are used to infer cloud top pressure, effective cloud amount, cloud thermodynamic phase, cloud optical thickness, and the effective size of cloud particles. The AIRS-based retrievals are compared with the counterparts of the operational cloud products derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). The two retrievals agree reasonably well except for the retrieved cloud effective particle size. Furthermore, the diurnal and seasonal contrasts of cloud properties are also investigated on the basis of the cloud properties retrieved from the AIRS data.
Author: