Geostationary Operational Environmental Satellite Sounder Research Articles

Evaluating possible enhancement of INSAT-3D Sounder water vapour retrieval in the tropics

The present study makes an attempt to use hyperspectral infrared observations to define optimum sounding instrument on board Indian geostationary satellites. In a multichannel sounding instrument such as Indian National Satellite System (INSAT-3D) and Geostationary Operational Environmental Satellite Sounder, there are three channels in 6–8 µm water vapour (WV) absorption band. In this study, humidity profiles are retrieved by adding another eight channels within 6–8 µm WV absorption band. The retrieved humidity profiles are compared with that retrieved from the hyperspectral sounding instrument Infrared Atmospheric Sounding Interferometer (IASI). It has been found that improvement in humidity profile retrieval with additional eight WV channels is merely ~1%, above the mid-troposphere compared to the profiles retrieved with just three WV channels. However, the retrieval accuracy with that obtained from the IASI spectra has improved by 5–10% compared to existing three as well as eight additional WV channels of a multichannel sounder. This study concludes that in order to improve the humidity retrieval accuracy in the tropics, hyperspectral sounding observations are required since mere increasing of WV channels in a multichannel sounder is having only a small positive impact.

Applications of Full Spatial Resolution Space-Based Advanced Infrared Soundings in the Preconvection Environment

Abstract Advanced infrared (IR) sounders such as the Atmospheric Infrared Sounder (AIRS) and Infrared Atmospheric Sounding Interferometer (IASI) provide atmospheric temperature and moisture profiles with high vertical resolution and high accuracy in preconvection environments. The derived atmospheric stability indices such as convective available potential energy (CAPE) and lifted index (LI) from advanced IR soundings can provide critical information 1 ~ 6 h before the development of severe convective storms. Three convective storms are selected for the evaluation of applying AIRS full spatial resolution soundings and the derived products on providing warning information in the preconvection environments. In the first case, the AIRS full spatial resolution soundings revealed local extremely high atmospheric instability 3 h ahead of the convection on the leading edge of a frontal system, while the second case demonstrates that the extremely high atmospheric instability is associated with the local development of severe thunderstorm in the following hours. The third case is a local severe storm that occurred on 7–8 August 2010 in Zhou Qu, China, which caused more than 1400 deaths and left another 300 or more people missing. The AIRS full spatial resolution LI product shows the atmospheric instability 3.5 h before the storm genesis. The CAPE and LI from AIRS full spatial resolution and operational AIRS/AMSU soundings along with Geostationary Operational Environmental Satellite (GOES) Sounder derived product image (DPI) products were analyzed and compared. Case studies show that full spatial resolution AIRS retrievals provide more useful warning information in the preconvection environments for determining favorable locations for convective initiation (CI) than do the coarser spatial resolution operational soundings and lower spectral resolution GOES Sounder retrievals.

Warning Information in a Preconvection Environment from the Geostationary Advanced Infrared Sounding System—A Simulation Study Using the IHOP Case

Abstract In this paper, a convective initiation event from the International H2O Project (IHOP) field experiment is used to demonstrate the potential utility of a future geostationary advanced infrared (IR) sounder for severe storm nowcasting applications. An advanced IR sounder would provide detailed stability information (e.g., lifted index and other parameters) with high temporal resolution useful for determining favorable locations for convective initiation. Atmospheric data from a high-resolution Weather Research and Forecasting model simulation was used to generate simulated Hyperspectral Environmental Suite (HES) and Advanced Baseline Imager (ABI) stability products. Comparison of these products shows that the ABI [or the current Geostationary Operational Environmental Satellite (GOES) Sounder] provides limited stability information before the storm development as a result of the limited spectral IR information for temperature and moisture profiling. The high spatial and temporal geostationary advanced IR sounder, however, can provide critical information about the destabilization much earlier than the current GOES Sounder or ABI.

Forecasting and nowcasting improvement in cloudy regions with high temporal GOES sounder infrared radiance measurements

In an effort to extend the high temporal resolution Geostationary Operational Environmental Satellite (GOES) infrared sounding retrievals from clear to cloudy skies, a synthetic regression‐based cloudy sounding retrieval algorithm has been developed and applied to GOES 12 sounder measurements. Comparisons against radiosondes at the Atmospheric Radiation Measurement Program at Southern Great Plains site from August 2006 to May 2007 and the conventional radiosondes network over the continental United States from January 2007 to November 2008 both show that the retrievals of moisture under thin cloud conditions perform similarly to those under the clear‐sky conditions. The largest improvements are found in the upper level integrated precipitable water vapor (PW) or PW3. Also in the case of low thick clouds, PW3 is usually improved significantly. In addition, the retrieved cloud parameters are consistent with the false RGB composite images. With the addition of the soundings under low thick or thin cloud conditions, the area without soundings is reduced by 57% in the selected case. The application to a tornadic storm on 24 April 2007 reveals that the GOES cloudy sounding retrievals are more useful at the early stage of the storm, when nearby clouds are considered thin or broken. The GOES cloudy sounding algorithm reveals more pronounced and extensive convective instability, and it does so earlier than the clear‐sky‐only results. The cloudy sounding retrievals have the potential to provide an earlier warning to forecasters.

Retrieving clear‐sky atmospheric parameters from SEVIRI and ABI infrared radiances

The algorithm for the current Geostationary Operational Environmental Satellite (GOES) Sounders is adapted to produce atmospheric temperature and moisture legacy profiles from simulated infrared radiances of the Advanced Baseline Imager (ABI) on board the next generation GOES‐R. Since the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board the Meteosat Second Generation (MSG) Meteosat‐8/9 has many of the same spectral and spatial features as ABI, it is used as proxy to test the algorithm. Because as imagers, SEVIRI and ABI do not have enough CO2 absorption spectral bands relative to the current GOES Sounders, the legacy profile algorithm for the current GOES Sounders needs to be modified. Both simulations and analysis with radiance measurements indicate that the single temperature‐sensitive infrared band (13.4 μm) of SEVIRI cannot provide enough temperature profile information. However, SEVIRI's two H2O absorption spectral bands (6.2 and 7.2 μm) are able to provide useful information on water vapor content above 700 hPa. Because of their high spatial (approximately 3 km for SEVIRI and 2 km for ABI IR bands) and high temporal (15 min full disk coverage) resolutions, SEVIRI and ABI will provide useful profile products with a quality similar to that from the current GOES Sounder prior to the availability of a hyperspectral IR sounding system in geostationary orbit.

Using the GOES Sounder to monitor upper level SO2 from volcanic eruptions

This study explores the sensitivity of the Geostationary Operational Environmental Satellite (GOES) Sounder observations to atmospheric loadings of SO2.from volcanic eruptions. The GOES Sounder offers a more rapid refresh rate than similar instruments on board polar‐orbiting satellites, such as the High‐Resolution Infrared Radiation Sounder (HIRS) carried on the NOAA and MetOp spacecraft. One of the GOES Sounder's 19 channels is in an SO2 absorption band. Simulations demonstrate that this channel, centered at approximately 7.4 mm, when combined with other channels, can detect the presence of large amounts of SO2 (e.g., greater than 50 DU) in the upper atmosphere (e.g., above 8 km). The GOES Sounder can also provide upper limits of the amount of upper level SO2, provided the atmospheric altitude of the SO2 is known. The sensitivity is demonstrated on two volcanic eruptions of the Soufrière Hills Volcano on the island of Montserrat. Through use of the GOES Sounder measurements, the advection and rapid spreading of the plume are easily observed. Efforts to fully characterize the plume size and transport are hampered by the limited spatial coverage of the current GOES Sounder.

High temporal resolution GOES sounder single field of view ozone improvements

A new total column ozone (TCO) algorithm for Geostationary Operational Environmental Satellite (GOES) Sounder data has been evaluated with the collocated 17 months (May 1998 through September 1999) Total Ozone Mapping Spectrometer (TOMS) measurements and GOES‐8 Sounder ozone retrievals. The new GOES ozone algorithm retrieves hourly TCO over the Continental United States (CONUS) to an accuracy of about 4.6% root mean square error (RMSE) as compared with previous algorithm accuracy of about 5.8%. The GOES TCO bias adjustment is also investigated and applied; both seasonal and latitudinal variations were found in the bias. Results show that bias correction is effective when applied to GOES TCO retrievals. OMI (Ozone Monitoring Instrument) data from the Earth Observing System Aura platform were used to validate the new algorithm. Good agreement was found between OMI and GOES‐12 single field‐of‐view (SFOV) TCO. The improved GOES TCO product is now available in real‐time for various applications.

A Comparison of GOES Sounder– and Cloud Lidar- and Radar-Retrieved Cloud-Top Heights

Abstract An assessment of the performance of the Geostationary Operational Environmental Satellite (GOES) sounder cloud-top pressure product is presented. GOES sounder cloud-top-height data were compared with values derived from a consensus cloud boundary dataset that utilizes data from a cloud lidar and a cloud radar located at the U.S. Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) Program’s Cloud and Radiation Test Bed (CART) site in Lamont, Oklahoma. Comparisons were performed from April 2000 to March 2002. A temporal filtering process was applied to the cloud lidar and cloud radar output so that a representative picture of the cloud field on the same spatial scale of the GOES sounder could be derived. Comparisons between the GOES sounder and ground-based cloud boundary measurements yielded a mean difference of 1772 m and a standard deviation of 1733 m. The difference between GOES cloud-top-height and ground-based retrievals is within ±500 m for 22% of the retrievals and within ±1500 m for 56% of the retrievals. These results are comparable to findings in similar studies that utilized the MODIS Airborne Simulator.

Synergistic Use of MODIS and AIRS in a Variational Retrieval of Cloud Parameters

Abstract The Moderate Resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS) measurements from the Earth Observing System's (EOS's) Aqua satellite enable global monitoring of the distribution of clouds. MODIS is able to provide a cloud mask, surface and cloud types, cloud phase, cloud-top pressure (CTP), effective cloud amount (ECA), cloud particle size, and cloud optical thickness at high spatial resolution (1–5 km). The combined MODIS–AIRS system offers the opportunity for improved cloud products, better than from either system alone; this improvement is demonstrated in this paper with both simulated and real radiances. A one-dimensional variational (1DVAR) methodology is used to retrieve the CTP and ECA from AIRS longwave (650–790 cm−1 or 15.38–12.65 μm) cloudy radiance measurements (hereinafter referred to as MODIS–AIRS 1DVAR). The MODIS–AIRS 1DVAR cloud properties show significant improvement over the MODIS-alone cloud properties and slight improvement over AIRS-alone cloud properties in a simulation study, while MODIS–AIRS 1DVAR is much more computationally efficient than the AIRS-alone 1DVAR; comparisons with radiosonde observations show that CTPs improve by 10–40 hPa for MODIS–AIRS CTPs over those from MODIS alone. The 1DVAR approach is applied to process the AIRS longwave cloudy radiance measurements; results are compared with MODIS and Geostationary Operational Environmental Satellite sounder cloud products. Data from ground-based instrumentation at the Atmospheric Radiation Measurement Program Cloud and Radiation Test Bed in Oklahoma are used for validation; results show that MODIS–AIRS improves the MODIS CTP, especially in low-level clouds. The operational use of a high-spatial-resolution imager, along with information from a high-spectral-resolution sounder will be possible with instruments planned for the next-generation geostationary operational instruments.

Volcanic ash detection and cloud top height estimates from the GOES‐12 imager: Coping without a 12 μm infrared band

The Geostationary Operational Environmental Satellite (GOES)‐12 Imager, which was activated 1 April 2003, has been re‐configured with the addition of a 13.3 μm Infrared (IR) spectral band, in place of the “split window” 12.0 μm band. Since the latter channel had been successfully used for volcanic ash detection from GOES for nearly ten years, there is some concern about the impact of this change on short term warnings and forecasts for aviation operations over North and South America. The first significant volcanic eruptions observed by the new GOES‐12 satellite occurred during 12–15 July 2003 at the Soufriere Hills Volcano, Montserrat. GOES‐12 was able to observe the eruption clouds adequately during this period using multi‐spectral techniques. Based on comparisons with multi‐spectral images from the GOES Sounder, GOES‐12 ash detection capability for this event was equal in quality to what would have been available from prior GOES with a 12.0 μm band.

Mathematical Aspects of the Meteorological Processing of Infrared Spectral Measurements from the GOES Sounder. Part III: Emissivity Estimation in Solving the Inverse Problem of Atmospheric Remote Sensing

Abstract To retrieve vertical profiles of temperature and moisture from infrared spectral measurements, surface emissivity must be accounted for in the physical solution of the inverse problem. A radiative model that includes the emission and reflection on the lower atmospheric boundary is introduced. An algorithm is developed for the solution of the vertical temperature–humidity profile and the estimation of an effective surface emissivity and temperature within the sounding area. Results using spectral measurements from the Geostationary Operational Environmental Satellite (GOES)-8 sounder are presented. It is found that accounting for the surface emissivity in the solution of the inverse problem has a positive impact on the meteorological profiles.

Mathematical Aspects in Meteorological Processing of Infrared Spectral Measurements from the GOES Sounder. Part II: Analysis of Spatial and Temporal Continuity of Spectral Measurements from theGOES-8Sounder

Abstract The spatial and temporal continuity of the infrared measurements from the Geostationary Operational Environmental Satellite (GOES)-8 sounder data are investigated, and an experimental processing approach is presented. Spatial filtering and cloud detection are performed in a joint algorithm: the preparation of the data for sounding analysis starts with spatial smoothing, followed by cloud detection, followed by averaging the clear-sky (cloud free) subsamples. Analysis of the sounder images reveals the presence of coherent noise on large spatial scales in some of the spectral bands. Analysis of a temporal sequence of spatially smoothed sounder images reveals regions of unphysical hourly change likely induced by instrument noise. A nonlinear temporal–spatial filtering algorithm is presented and tested that improves the noise filtering for the sounder spectral measurements and the thermodynamical spatial and temporal consistency of the sounding retrievals in the troposphere.

Validation of a Technique for Estimating OLR with the GOES Sounder

Abstract In order to eventually use the capability of the Geostationary Operational Environmental Satellite (GOES) Sounder to capture the diurnal signal of outgoing longwave radiation (OLR), it is necessary to establish its instantaneous accuracy. Error characteristics of OLR derived from the GOES Sounder are analyzed using Clouds and Earth's Radiant Energy System (CERES) observations. The comparisons are based on over 28 000 data collected in July 1998 and April 2000 over the continental United States. The July data correspond to observations from GOES-8 and -9 and the CERES instrument on board the Tropical Rainfall Measurement Mission (TRMM) satellite. The April data correspond to GOES-8 and -10, and two CERES instruments on board the Terra satellite. The comparisons are for instantaneous, homogeneous scenes of 1° × 1° boxes. Comparisons of GOES Sounder with collocated TRMM and Terra CERES OLR show instantaneous rms agreement to within about 7 W m−2 for day and/or night homogeneous scenes. The GOES tech...

Validation and Use of GOES Sounder Moisture Information

Abstract The Geostationary Operational Environmental Satellite (GOES) sounders have provided quality hourly radiances and derived products over the continental United States and adjacent oceans for more than five years. The products derived from the radiances include temperature and moisture profiles; total precipitable water vapor (TPW); atmospheric stability indices, such as convective available potential energy (CAPE) and lifted index (LI); cloud-top properties; total column ozone; and midlevel motion. This paper focuses on validation and use of moisture profiles derived in clear regions. Validations are made with respect to collocated radiosondes, a microwave radiometer, and parallel runs of the regional Eta Model system. The ground-based microwave radiometer enables comparisons throughout the day, instead of only at conventional radiosonde launch times (0000 and 1200 UTC). The validations show that the sounder products provide unique information about the state of the atmosphere. The GOES sounder moi...

Mathematical Aspects in Meteorological Processing of Infrared Spectral Measurements from the GOES Sounder. Part I: Constructing the Measurement Estimate Using Spatial Smoothing

Abstract The accuracy of temperature and moisture vertical profiles retrieved from infrared spectral measurements is dependent on accurate definition of all contributions from the observed “surface–atmosphere” system to the outgoing radiances. The associated inverse problem is ill posed. Instrument noise is a major contributor to errors in modeling spectral measurements. This paper considers an approach for noise reduction in the Geostationary Operational Environmental Satellite (GOES) spectral channels using spatial averaging that is based upon spectral characteristics of the measurements, spatial properties of atmospheric fields of temperature and moisture, and properties of the inverse problem. Spatial averaging over different fields of regard is studied for the GOES-8 sounder spectral bands. Results of the statistical analysis are presented.

Estimation of Total Atmospheric Ozone from GOES Sounder Radiances with High Temporal Resolution

Abstract The potential for using Geostationary Operational Environmental Satellite (GOES) Sounder radiance measurements to monitor total atmospheric ozone is examined. A statistical regression using GOES Sounder spectral bands 1–15 radiances allows estimation of total atmospheric ozone. Hourly GOES ozone products have been generated since May 1998. GOES ozone estimates are compared with Total Ozone Mapping Spectrometer (TOMS) ozone measurements from the Earth Probe satellite and ground-based Dobson spectrometer ozone observations. Results show that the percentage root-mean-square (rms) difference between instantaneous TOMS and GOES ozone estimates ranges from 4% to 7%. Also, daily comparisons for 1998 between GOES ozone values and ground-based observations at Bismarck, North Dakota; Wallops Island, Virginia; and Nashville, Tennessee, show that the rms difference is approximately 21 Dobson units. Given the hourly measurements and high-spatial density provided by the GOES Sounder, GOES ozone estimates and a...

NWP Cloud Initialization Using GOES Sounder Data and Improved Modeling of Nonprecipitating Clouds

Cloud-top pressures and effective cloud amounts, derived from Geostationary Operational Environmental Satellite (GOES) sounders, are used to specify a three-dimensional mesoscale cloud field for numerical weather prediction. A bulk cloud parameterization scheme based on relative humidity is introduced into the forecast model to efficiently use the satellite sounder observations. The cloud initialization and bulk cloud parameterization are tested in the Cooperative Institute for Meteorological Satellite Studies Regional Assimilation System for summer and winter periods. Comparisons between cloud forecasts and GOES cloud observations for four model configurations are presented. It is shown that the use of the initialization improved the areal coverage of the nonprecipitating clouds early in the forecast period, which translated to an improvement of the precipitation equitable threat score for the 24-h forecast (when the model initial time was 1200 UTC) and the 36-h forecast (when the model initial time was 0000 UTC).

Experimental GOES Sounder Products for the Assessment of Downburst Potential

Abstract Several experimental products derived from Geostationary Operational Environmental Satellite (GOES) Sounder retrievals (vertical profiles of temperature and moisture) have been developed to assist weather forecasters in assessing the potential for convective downbursts. The product suite currently includes the wind index (WINDEX), a dry microburst index, and the maximum difference in equivalent potential temperature (θe) from the surface to 300 hPa. The products are displayed as color-coded boxes or numerical values, superimposed on GOES visible, infrared, or water vapor imagery, and are available hourly, day and night, via the Internet. After two full summers of evaluation, the products have been shown to be useful in the assessment of atmospheric conditions that may lead to strong, gusty surface winds from thunderstorms. Two case studies are presented: 1) a severe downburst storm in southern Arizona that produced historic surface wind speeds and damage, and 2) multiple dry and wet downbursts in...

A Numerical Study of the Effect of GOES Sounder Cloud-Cleared Brightness Temperatures on the Prediction of Hurricane Felix

The influence of Geostationary Operational Environmental Satellite (GOES) brightness temperature data on the numerical simulations of Hurricane Felix is investigated. Satellite data are included as an augmentation to a bogus data assimilation (BDA) procedure using a mesoscale adjoint modeling system. The assimilation of satellite data modified not only the environmental flow but also the structure of the initial vortex, which is located over a region devoid of satellite data. This modification resulted in a reduction of the 12-h forecast errors verified by radiosonde data. Despite the fact that the forecast using only the bogus surface low at the initial time was very good, track and intensity forecasts beyond 2 days of model integration were shown to be improved further by including satellite data in the initialization procedure. Differences in the prediction of Hurricane Felix with and without satellite data were also found in the prediction of the upper-level jet, the cold temperature trough ahead of the hurricane, the size of the hurricane eye, and the location of the maximum hydrometeor. Although the focus of this study is to assess the effect of the direct use of satellite brightness temperature data on hurricane prediction, it is also noted that the BDA experiment including only the bogus data shows a positive effect of the BDA vortex on the environmental flow during the forecast period, as verified by satellite observations.

Improving Cloud and Moisture Representation in Weather Prediction Model Analyses with Geostationary Satellite Information

This paper develops a methodology for an experiment with several parallel regional Weather Research and Forecasting (WRF) model simulations initialized with satellite-based retrievals. The intent is to clarify the impact of observations, in the form of retrievals, from the Geostationary Operational Environmental Satellite (GOES) Sounder on 12, 24, and 36-hour WRF model forecasts of precipitable water. Two experimental analyses are built from a CIMSS Regional Assimilation System (CRAS) pre-forecast spin-up. The CRAS assimilates precipitable water and cloud products derived from the GOES Sounder. An experimentation period between late September and early October 2011 found that the majority of impact in the experimental simulations compared to the control is recognized in the total precipitable water field over the first 12 hours.Â