scholarly journals Improvement in tropospheric moisture retrievals from VIIRS through the use of infrared absorption bands constructed from VIIRS and CrIS data fusion

2020 ◽  
Author(s):  
E. Eva Borbas ◽  
Elisabeth Weisz ◽  
Chris Moeller ◽  
W. Paul Menzel ◽  
Bryan A. Baum
Keyword(s):  
Absorption Band ◽  
Data Fusion ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Precipitable Water ◽  
Ir Absorption ◽  
Absorption Bands ◽  
Total Precipitable Water ◽  
Upper Tropospheric Humidity ◽  
Operational Data

Abstract. An operational data product available for both the Suomi-NPP and NOAA-20 platforms provides high spatial resolution infrared (IR) absorption band radiances for VIIRS based on a VIIRS+CrIS data fusion method. This study investigates the use of these IR radiances, centered at 4.5, 6.7, 7.3, 9.7, 13.3, 13.6, 13.9, and 14.2 µm, to construct atmospheric moisture products (e.g., total precipitable water and upper tropospheric humidity) and to evaluate their accuracy. Total precipitable water (TPW) and upper tropospheric humidity (UTH) retrieved from hyperspectral sounder CrIS measurements are provided at the associated VIIRS sensor's high spatial resolution (750 m) and are compared subsequently to collocated operational Aqua MODIS and Suomi-NPP VIIRS moisture products. This study suggests that the use of VIIRS IR absorption band radiances will provide continuity with Aqua MODIS moisture products.

scholarly journals Improvement in tropospheric moisture retrievals from VIIRS through the use of infrared absorption bands constructed from VIIRS and CrIS data fusion

2021 ◽  
Vol 14 (2) ◽  
pp. 1191-1203
Author(s):  
E. Eva Borbas ◽  
Elisabeth Weisz ◽  
Chris Moeller ◽  
W. Paul Menzel ◽  
Bryan A. Baum
Keyword(s):  
Absorption Band ◽  
Data Fusion ◽  
Spatial Resolution ◽  
Infrared Imaging ◽  
High Spatial Resolution ◽  
Precipitable Water ◽  
Ir Absorption ◽  
Absorption Bands ◽  
Total Precipitable Water ◽  
Upper Tropospheric Humidity

Abstract. An operational data product available for both the Suomi National Polar-orbiting Partnership (S-NPP) and National Oceanic and Atmospheric Administration-20 (NOAA-20) platforms provides high-spatial-resolution infrared (IR) absorption band radiances for Visible Infrared Imaging Radiometer Suite (VIIRS) based on a VIIRS and Crosstrack Infrared Sounder (CrIS) data fusion method. This study investigates the use of these IR radiances, centered at 4.5, 6.7, 7.3, 9.7, 13.3, 13.6, 13.9, and 14.2 µm, to construct atmospheric moisture products (e.g., total precipitable water and upper tropospheric humidity) and to evaluate their accuracy. Total precipitable water (TPW) and upper tropospheric humidity (UTH) retrieved from hyperspectral sounder CrIS measurements are provided at the associated VIIRS sensor's high spatial resolution (750 m) and are compared subsequently to collocated operational Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) and S-NPP VIIRS moisture products. This study suggests that the use of VIIRS IR absorption band radiances will provide continuity with Aqua MODIS moisture products.

scholarly journals Local vibrational modes of vacancy-oxygen-related complexes at room temperature

2020 ◽  
Vol 56 (4) ◽  
pp. 480-487
Author(s):  
E. A. Tolkacheva ◽  
V. P. Markevich ◽  
L. I. Murin
Keyword(s):  
Absorption Band ◽  
Room Temperature ◽  
Clear Correlation ◽  
Ir Absorption ◽  
Oxygen Impurity ◽  
Interstitial Oxygen ◽  
Vibrational Modes ◽  
Oxygen Defect ◽  
Absorption Bands ◽  
Local Vibrational Modes

The isotopic content of natural silicon (28Si (92.23 %), 29Si (4.68 %) и 30Si (3.09 %)) affects noticeably the shape of IR absorption bands related to the oxygen impurity atoms. In the present work an attempt is undertaken to determine the positions of local vibrational modes (LVMs), related to quasimolecules 28Si16OS29Si and 28Si16OS30Si (OS – substitutional oxygen atom), for the absorption spectra measured at room temperature. An estimation of the isotopic shifts of corresponding modes is done by fitting the shape of the experimentally measured absorption band related to the vacancy–oxygen center in irradiated Si crystals. The LVM isotope shifts are found to be equal 2,2 ± 0.25 cm–1 for 28Si-16OS29Si and 4,3 ± 0,9 см–1 for 28Si-16OS30Si in relation to the basic band due to 28Si-16OS28Si, and the full width at half maximum of the A-center absorption band (28Si-16OS28Si) is 5,3 ± 0.25 cm–1. By means of infrared absorption spectroscopy a clear correlation between the disappearance of the divacancy (V2) in the temperature range 200–275 ºС and appearance of two absorption bands with their maxima at 825.8 and 839.2 cm–1 in irradiated oxygen-rich Si crystals is found. The band positioned at 825.8 cm–1 is assigned to a divacancy-oxygen defect V2O formed via an interaction of mobile V2 with interstitial oxygen (Oi ) atoms. The 839.2 cm–1 band is much more pronounced in neutron irradiated samples as compared to samples irradiated with electrons. We argue that it is related to a trivacancy–oxygen defect (V3O) formed via an interaction of mobile V3 with Oi atoms.

EMCCD-SPAD Camera data fusion for high spatial resolution time-of-flight imaging.

2019 ◽  
Author(s):  
Clara Callenberg ◽  
Ashley Lyons ◽  
Dennis den Brok ◽  
Robert Henderson ◽  
Matthias B. Hullin ◽  
...  
Keyword(s):  
Data Fusion ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Time Of Flight ◽  
Resolution Time ◽  
Time Of Flight Imaging

scholarly journals An Approach for Improving Cirrus Cloud-Top Pressure/Height Estimation by Merging High-Spatial-Resolution Infrared-Window Imager Data with High-Spectral-Resolution Sounder Data

2012 ◽  
Vol 51 (8) ◽  
pp. 1477-1488 ◽  
Author(s):  
Elisabeth Weisz ◽  
W. Paul Menzel ◽  
Nadia Smith ◽  
Richard Frey ◽  
Eva E. Borbas ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Infrared Imaging ◽  
High Spatial Resolution ◽  
High Sensitivity ◽  
Satellite Observation ◽  
High Spectral Resolution ◽  
Vertical Resolution ◽  
Absorption Bands ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Cloud Top Pressure

AbstractThe next-generation Visible and Infrared Imaging Radiometer Suite (VIIRS) offers infrared (IR)-window measurements with a horizontal spatial resolution of at least 1 km, but it lacks IR spectral bands that are sensitive to absorption by carbon dioxide (CO2) or water vapor (H2O). The CO2 and H2O absorption bands have high sensitivity for the inference of cloud-top pressure (CTP), especially for semitransparent ice clouds. To account for the lack of vertical resolution, the “merging gradient” (MG) approach is introduced, wherein the high spatial resolution of an imager is combined with the high vertical resolution of a sounder for improved CTP retrievals. The Cross-Track Infrared Sounder (CrIS) is on the same payload as VIIRS. In this paper Moderate Resolution Imaging Spectroradiometer (MODIS) and Atmospheric Infrared Sounder (AIRS) data are used as proxies for VIIRS and CrIS, respectively, although the approach can be applied to any imager–sounder pair. The MG method establishes a regression relationship between gradients in both the sounder radiances convolved to imager bands and the sounder CTP retrievals. This relationship is then applied to the imager radiance measurements to obtain CTP retrievals at imager spatial resolution. Comparisons with Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) cloud altitudes are presented for a variety of cloud scenes. Results demonstrate the ability of the MG algorithm to add spatial definition to the sounder retrievals with a higher accuracy and precision than those obtained solely from the imager.

scholarly journals A Photoelectric Hygrometer*

1947 ◽  
Vol 28 (7) ◽  
pp. 330-334 ◽  
Author(s):  
Bernard Hamermesh ◽  
Frederick Reines ◽  
Serge A. Korff
Keyword(s):  
Water Vapor ◽  
Absorption Band ◽  
Absolute Humidity ◽  
Precipitable Water ◽  
The Other ◽  
Water Vapor Absorption ◽  
Absorption Bands ◽  
Vapor Absorption ◽  
Dispersing System ◽  
Humidity Range

An instrument that measures small absolute humidity changes by the photoelectric examination of the 9,440 Ångstrom-units absorption band of water vapor is described. The instrument consists of a small source of light which sends its radiation over an air path of less than one and a half meters to a dispersing system. The resulting spectrum then is allowed to fall on two vacuum phototubes; one centered in the 9,400 Ångstrom-units absorption band of water vapor, the other located at 8,000 ngstrom units where no water vapor absorption bands exist. As the absolute humidity in the air path is varied, the phototube in the region of the band is affected; whereas the reference phototube is not. The phototubes are arranged in an amplifying circuit so as to magnify the effect of varying humidity. The instrument uses a portable microammeter instead of the sensitive galvanometer of all previous spectral hygrometers. Humidity changes of 2 to 8 × 10−5 centimeter of precipitable water path over 143 centimeters of air path can be measured. An investigation of the small sensitive range of the instrument was carried out and the results indicate that the device is confined to use over a small humidity range with equipment available at the present time.

scholarly journals A new approach to accurate validation of remote sensing retrieval of evapotranspiration based on data fusion

2010 ◽  
Vol 7 (2) ◽  
pp. 1745-1784 ◽  
Author(s):  
C. Sun ◽  
D. Jiang ◽  
J. Wang ◽  
Y. Zhu
Keyword(s):  
Remote Sensing ◽  
Data Fusion ◽  
Spatial Resolution ◽  
Hydrological Model ◽  
Assessment Tool ◽  
High Spatial Resolution ◽  
Meteorological Data ◽  
New Method ◽  
Distributed Hydrological Model ◽  
New Approach

Abstract. The study presented a new method of validating the remote-sensing (RS) retrieval of evapotranspiration (ET) under the support of a distributed hydrological model: Soil and Water Assessment Tool (SWAT). In this method, the output runoff data based on a fusion of ET data, meteorological data and rainfall data, etc. were compared with the observed runoff data, so as to carry out validation analysis. A new pattern of validating the ET data obtained from RS retrieval, which was more appropriate than the conventional means of observing the ET at several limited stations based on eddy covariance, was proposed. It has integrated the advantage of high requirement of ET with high spatial resolution in the distributed hydrological model and that of the capacity of providing ET with high spatial resolution in RS methods. First, the ET data in five years (2000–2004) were retrieved with RS according to the principle of energy balance. The temporal/spatial ditribution of monthly ET data and related causes were analyzed in the year of 2000, and the monthly ET in the five years was calculated according to the PM model. Subsequently, the results of the RS retrieval of ET and the PM-based ET calculation were compared and validated. Finnaly, the ET data obtained from RS retrieval was evaluated with the new method, under the support of SWAT, meteorologic data, Digital Elevation Model (DEM), landuse data and soil data, etc. as the input, being compared with the PM-based ET. According to the ET data analysis, it can be inferred that the ET obtained from RS retrieval was more continuous and stable with less saltation, while the PM-based ET presented saltation, especially in the year of 2000 and 2001. The correlation coefficient between the monthly ET in two methods reaches 0.8914, which could be explained by the influence from clouds and the inadequate representativeness of the meteorologic stations. Moreover, the PM-based ET was smaller than the ET obtained from RS retrieval, which was in accordance with previous studies (Jamieson, 1982; Dugas and Ainsworth, 1985; Benson et al., 1992; Pereira and Nova, 1992). After the data fusion, the correlation (R2=0.8516) between the monthly runoff obtained from the simulation based on ET retrieval and the observed data was higher than that (R2=0.8411) between the data obtained from the PM-based ET simulation and the observed data. As for the RMSE, the result (RMSE=26.0860) between the simulated runoff based on ET retrieval and the observed data was also superior to the result (RMSE=35.71904) between the simulated runoff obtained with PM-based ET and the observed data. As for the MBE parameter, the result (MBE=−8.6578) for the RS retrieval method was obviously better than that (MBE=−22.7313) for the PM-based method. The comparison of them showed that the RS retrieval had better adaptivity and higher accuracy than the PM-based method, and the new approach based on data fusion and the distributed hydrological model was feasible, reliable and worth being studied further.

scholarly journals High-spatial-resolution mapping of precipitable water vapour using SAR interferograms, GPS observations and ERA-Interim reanalysis

2016 ◽  
Vol 9 (9) ◽  
pp. 4487-4501 ◽  
Author(s):  
Wei Tang ◽  
Mingsheng Liao ◽  
Lu Zhang ◽  
Wei Li ◽  
Weimin Yu
Keyword(s):  
Synthetic Aperture Radar ◽  
Water Vapour ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
High Spatial Resolution ◽  
Precipitable Water ◽  
Synthetic Aperture ◽  
Precipitable Water Vapour ◽  
Radar Images ◽  
Aperture Radar

Abstract. A high spatial and temporal resolution of the precipitable water vapour (PWV) in the atmosphere is a key requirement for the short-scale weather forecasting and climate research. The aim of this work is to derive temporally differenced maps of the spatial distribution of PWV by analysing the tropospheric delay "noise" in interferometric synthetic aperture radar (InSAR). Time series maps of differential PWV were obtained by processing a set of ENVISAT ASAR (Advanced Synthetic Aperture Radar) images covering the area of southern California, USA from 6 October 2007 to 29 November 2008. To get a more accurate PWV, the component of hydrostatic delay was calculated and subtracted by using ERA-Interim reanalysis products. In addition, the ERA-Interim was used to compute the conversion factors required to convert the zenith wet delay to water vapour. The InSAR-derived differential PWV maps were calibrated by means of the GPS PWV measurements over the study area. We validated our results against the measurements of PWV derived from the Medium Resolution Imaging Spectrometer (MERIS) which was located together with the ASAR sensor on board the ENVISAT satellite. Our comparative results show strong spatial correlations between the two data sets. The difference maps have Gaussian distributions with mean values close to zero and standard deviations below 2 mm. The advantage of the InSAR technique is that it provides water vapour distribution with a spatial resolution as fine as 20 m and an accuracy of ∼ 2 mm. Such high-spatial-resolution maps of PWV could lead to much greater accuracy in meteorological understanding and quantitative precipitation forecasts. With the launch of Sentinel-1A and Sentinel-1B satellites, every few days (6 days) new SAR images can be acquired with a wide swath up to 250 km, enabling a unique operational service for InSAR-based water vapour maps with unprecedented spatial and temporal resolution.

scholarly journals Using Sounder Data to Improve Cirrus Cloud Height Estimation from Satellite Imagers

2019 ◽  
Vol 36 (7) ◽  
pp. 1331-1342 ◽  
Author(s):  
Andrew K. Heidinger ◽  
Nicholas Bearson ◽  
Michael J. Foster ◽  
Yue Li ◽  
Steve Wanzong ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Optimal Estimation ◽  
Additional Constraint ◽  
Spectral Information ◽  
Cirrus Cloud ◽  
Absorption Bands ◽  
Cloud Height ◽  
Cross Track ◽  
The Impact

AbstractModern polar-orbiting meteorological satellites provide both imaging and sounding observations simultaneously. Most imagers, however, do not have H2O and CO2 absorption bands and therefore struggle to accurately estimate the height of optically thin cirrus clouds. Sounders provide these needed observations, but at a spatial resolution that is too coarse to resolve many important cloud structures. This paper presents a technique to merge sounder and imager observations with the goal of maintaining the details offered by the imager’s high spatial resolution and the accuracy offered by the sounder’s spectral information. The technique involves deriving cloud temperatures from the sounder observations, interpolating the sounder temperatures to the imager pixels, and using the sounder temperatures as an additional constraint in the imager cloud height optimal estimation approach. This technique is demonstrated using collocated VIIRS and Cross-track Infrared Sounder (CrIS) observations with the impact of the sounder observations validated using coincident CALIPSO/CALIOP cloud heights These comparisons show significant improvement in the cloud heights for optically thin cirrus. The technique should be generally applicable to other imager/sounder pairs.

Data fusion for high spatial resolution LAI estimation

2014 ◽  
Vol 16 ◽  
pp. 59-67 ◽  
Author(s):  
Carmen Hernández ◽  
Leónia Nunes ◽  
Domingos Lopes ◽  
Manuel Graña
Keyword(s):  
Data Fusion ◽  
Spatial Resolution ◽  
High Spatial Resolution
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