2,340 research outputs found
Improving Soil Moisture States in WRF-Hydro Using SWOT Observations
No abstract availabl
Limb Correction of VIIRS and SEVIRI IR Channels for the Improved Interpretation of RGB Composites
No abstract availabl
Assimilating SWOT Water Surface Elevations into the WRF-Hydro Modeling System in Alaska Using HydroDART
No abstract availabl
Limb Correction of Infrared Imagery in Cloudy Regions for the Improved Interpretation of RGB Composites
Red-Green-Blue (RGB) composites (EUMETSAT User Services 2009) combine information from several channels into a single composite image. RGB composites contain the same information as the original channels, but presents the information in a more efficient manner. However, RGB composites derived from infrared imagery of both polar-orbiting and geostationary sensors are adversely affected by the limb effect, which interferes with the qualitative interpretation of RGB composites at large viewing zenith angles. The limb effect, or limb-cooling, is a result of an increase in optical path length of the absorbing atmosphere as viewing zenith angle increases (Goldberg et al. 2001; Joyce et al. 2001; Liu and Weng 2007). As a result, greater atmospheric absorption occurs at the limb, causing the sensor to observe anomalously cooler brightness temperatures. Figure 1 illustrates this effect. In general, limb-cooling results in a 4-11 K decrease in measured brightness temperature (Liu and Weng 2007) depending on the infrared band. For example, water vapor and ozone absorption channels display much larger limb-cooling than infrared window channels. Consequently, RGB composites created from infrared imagery not corrected for limb effects can only be reliably interpreted close to nadir, which reduces the spatial coverage of the available imagery. Elmer (2015) developed a reliable, operational limb correction technique for clear regions. However, many RGB composites are intended to be used and interpreted in cloudy regions, so a limb correction methodology valid for both clear and cloudy regions is needed. This paper presents a limb correction technique valid for both clear and cloudy regions, which is described in Section 2. Section 3 presents several RGB case studies demonstrating the improved functionality of limb-corrected RGBs in both clear and cloudy regions, and Section 4 summarizes and presents the key conclusions of this work
The Impact of the Assimilation of Hyperspectral Infrared Retrieved Profiles on Advanced Weather and Research Model Simulations of a Non-Convective Wind Event
Non-convective wind events commonly occur with passing extratropical cyclones and have
significant societal and economic impacts. Since non-convective winds often occur in the
absence of specific phenomena such as a thunderstorm, tornado, or hurricane, the public are less
likely to heed high wind warnings and continue daily activities. Thus non-convective wind
events result in as many fatalities as straight line thunderstorm winds. One physical explanation
for non-convective winds includes tropopause folds. Improved model representation of
stratospheric air and associated non-convective wind events could improve non-convective wind
forecasts and associated warnings. In recent years, satellite data assimilation has improved skill
in forecasting extratropical cyclones; however errors still remain in forecasting the position and
strength of extratropical cyclones as well as the tropopause folding process. The goal of this
study is to determine the impact of assimilating satellite temperature and moisture retrieved
profiles from hyperspectral infrared (IR) sounders (i.e. Atmospheric Infrared Sounder (AIRS),
Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric
Sounding Interferometer (IASI)) on the model representation of the tropopause fold and an
associated high wind event that impacted the Northeast United States on 09 February 2013.
Model simulations using the Advanced Research Weather Research and Forecasting Model
(ARW) were conducted on a 12-km grid with cycled data assimilation mimicking the operational
North American Model (NAM). The results from the satellite assimilation run are compared to a
control experiment (without hyperspectral IR retrievals), Modern Era-Retrospective Analysis for
Research and Applications (MERRA) reanalysis, and Rapid Refresh analyses
The Impact of the Assimilation of Hyperspectral Infrared Retrieved Profiles on Advanced Weather and Research Model Simulations of a Non-Convective Wind Event
No abstract availabl
Analysis and Applications of Water Vapor-Derived Multispectral Composites for Geostationary Satellites
Analysis of multispectral (red-green-blue, RGB) satellite image composites can be used to improve understanding of thermodynamic and / or dynamic features associated with the development of significant weather events (cyclones, hurricanes, intense convection, turbulence, etc.) The enhanced water vapor imaging capabilities of the Advanced Baseline Imager on GOES-16 and GOES-17 satellites provide a unique opportunity to demonstrate this capability through a comparison of the Air Mass (AM) and Differential Water Vapor (DWV) RGB image products for several case studies
Impacts of Real-Time Satellite-Derived Vegetation on WRF-Hydro Simulated Streamflow
No abstract availabl
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