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NASA NTRS2024

Deducing Land-Atmosphere Coupling Regimes from SMAP Soil Moisture

In recent years, there has been a growing recognition of the significance of Land-Atmosphere (L-A) interactions and feedback mechanisms in understanding and predicting Earth’s water and energy cycles. Soil moisture plays a critical role in mediating the strength of L-A interactions and is important for understanding the complex and governing processes across this interface. This study aims to identify the significance of soil moisture in identifying L-A coupling strength within the Convective Triggering Potential (CTP) and Humidity Index (HI) framework. To address this, a consistent and reliable dataset of atmospheric profiles is created by merging CTP and HI using Triple Collocation (TC) with three reanalysis datasets. The merged CTP and HI product demonstrates enhanced performance globally as compared to the individual datasets when validated with radiosonde and satellite observations. This merged product of CTP and HI is then used to compare the L-A coupling strength based on Soil Moisture Active Passive Level 3 (SMAPL3) and SMAP Level 4 (SMAPL4) over two decades (2003-2022) where L-A coupling strength is defined as the persistence probability within the dry and wet coupling regimes. Results indicate that the persistency-based coupling strength is related to the ability of soil moisture to predict future atmospheric humidity and dry vs. wet coupling state. The coupling strength in SMAPL4 is consistently stronger than in SMAPL3 and is likely due to its reliance on a land surface model and reduced susceptibility to random noise. The difference in coupling strength based on the same CTP-HI underscores the importance of soil moisture data in estimating coupling strength within the CTP-HI framework. These findings lay the groundwork for understanding the role of L-A interactions and drought evolution due to soil moisture variations, by providing insight into the quantification of coupling strength and its role in drought monitoring and forecast efforts.

Land-atmosphere coupling↗
NASA NTRS1998

Remote Sensing Measurements of Vertical and Horizontal Moisture Variations from Aircraft Instruments

The research in this paper focuses on describing vertical and horizontal of water vapor variability using two remote sensing aircraft instruments. To achieve this goal we will compare precipitable water and upper level humidity estimates derived from the each of the instruments. The Multispectral Atmospheric Mapping Sensor (MAMS) is a visible and infrared radiometer with similar channels to that of the GOES imager. MAMS has flown aboard the NASA ER-2 numerous times. It has been used to validate features observed with the previous series of GOES satellites. MAMS data has been used to study precipitable water and upper level water vapor as well as other geophysical parameters. MAMS provides the opportunity to obtain water vapor Imagery at 6.7 mm. Upper tropospheric humidity can be computed using this channel in a similar fashion to that of Soden and Bretherton. In addition to the water vapor channel, MAMS records data In 3 other Infrared channels and 8 visible and near Infrared bands at high spatial resolution (I 00 Abstract: m). The 1 1 and 12 mm infrared channels allow for the application of a split technique to derive total precipitable water. The Udar Atmospheric Sensing Experiment (LASE) which uses the Differential Absorption Udar (DIAL) technique for obtaining simultaneous water vapor and aerosol profiles through the entire troposphere. LASE operates In the 81 5 nm wavelength region and uses a double pulsed Ti:sapphire laser that is locked onto a water vapor line. LASE has good horizontal (IO km) and excellent vertical (300 m) resolution. MAMS and LASE collected data simultaneously on several ER-2 flights in September 1995. LASE mixing ratio profiles will be Integrated for comparison with MAMS precipitable water estimates and the upper tropospheric humidity will be computed for the layer observed by the MAMS 6.7 mm channel for comparison for this time period. Results show a significant correlation between the measurements of the two Instruments. Regions of high/low upper tropospheric humidity are apparent In measurements from both instruments. Also changes in boundary layer moisture depicted by LASE are reflected in the total precipitable water measured by MAMS.

Atkinson, R. J.↗
NASA NTRS2020

Influence of Cloud, Fog, and High Relative Humidity during Pollution Transport Events in South Korea: Aerosol Properties and PM2.5 Variability

This investigation examines aerosol dynamics during major fine mode aerosol transboundary pollution events in South Korea primarily during the KORUS-AQ campaign from May 1 – June 10, 2016, particularly when cloud fraction was high and/or fog was present to quantify the change in aerosol characteristics due to near-cloud or fog interaction. We analyze the new AERONET Version 3 data that have significant changes to cloud screening algorithms, allowing many more fine-mode observations in the near vicinity of clouds or fog. Case studies for detailed investigation include May 25–26, 2016 when cloud fraction was high over much of the peninsula, associated with a weak frontal passage and advection of pollution from China. These cloud-influenced Chinese transport dates also had the highest aerosol optical depth (AOD), surface PM2.5 concentrations and fine mode particle sizes of the entire campaign. Another likewise cloud/high relative humidity (RH) case is June 9 and 10, 2016 when fog was present over the Yellow Sea that appears to have affected aerosol properties well downwind over the Korean peninsula. In comparison we also investigated aerosol properties on air stagnation days with very low cloud cover and relatively low RH (May 17 & 18, 2016), when local Korean emissions dominated. Aerosol volume size distributions show marked differences between the transport days (with high RH and cloud influences) and the local pollution stagnation days, with total column-integrated particle fine mode volume being an order of magnitude greater on the pollution transport dates. The PM2.5 over central Seoul were significantly greater than for coastal sites on the transboundary transport days yet not on stagnation days, suggesting addi-tional particle formation from gaseous urban emissions in cloud/fog droplets and/or in the high RH humidified aerosol environment. Many days had KORUS-AQ research aircraft flights that provided observations of aerosol absorption, particle chemistry and vertical profiles of extinction. AERONET retrievals and aircraft in situ mea-surements both showed high single scattering albedo (weak absorption) on the cloudy or cloud influenced days, plus aircraft profile in situ measurements showed large AOD enhancements (versus dried aerosol) at ambient relative humidity (RH) on the pollution transport days, consistent with the significantly larger fine mode particle radii and weak absorption.

Aerosol↗
NASA NTRS2012

High-Altitude MMIC Sounding Radiometer for the Global Hawk Unmanned Aerial Vehicle

Microwave imaging radiometers operating in the 50-183 GHz range for retrieving atmospheric temperature and water vapor profiles from airborne platforms have been limited in the spatial scales of atmospheric structures that are resolved not because of antenna aperture size, but because of high receiver noise masking the small variations that occur on small spatial scales. Atmospheric variability on short spatial and temporal scales (second/ km scale) is completely unresolved by existing microwave profilers. The solution was to integrate JPL-designed, high-frequency, low-noise-amplifier (LNA) technology into the High-Altitude MMIC Sounding Radiometer (HAMSR), which is an airborne microwave sounding radiometer, to lower the system noise by an order of magnitude to enable the instrument to resolve atmospheric variability on small spatial and temporal scales. HAMSR has eight sounding channels near the 60-GHz oxygen line complex, ten channels near the 118.75-GHz oxygen line, and seven channels near the 183.31-GHz water vapor line. The HAMSR receiver system consists of three heterodyne spectrometers covering the three bands. The antenna system consists of two back-to-back reflectors that rotate together at a programmable scan rate via a stepper motor. A single full rotation includes the swath below the aircraft followed by observations of ambient (roughly 0 C in flight) and heated (70 C) blackbody calibration targets located at the top of the rotation. A field-programmable gate array (FPGA) is used to read the digitized radiometer counts and receive the reflector position from the scan motor encoder, which are then sent to a microprocessor and packed into data files. The microprocessor additionally reads telemetry data from 40 onboard housekeeping channels (containing instrument temperatures), and receives packets from an onboard navigation unit, which provides GPS time and position as well as independent attitude information (e.g., heading, roll, pitch, and yaw). The raw data files are accessed through an Ethernet port. The HAMSR data rate is relatively low at 75 kbps, allowing for real-time access over the Global Hawk high-data-rate downlink. Once on the ground, the raw data are unpacked and processed through two levels of processing. The Level 1 product contains geo-located, time-stamped, calibrated brightness temperatures for the Earth scan. These data are then input to a lD variational retrieval algorithm to produce temperature, water vapor, and cloud liquid water profiles, as well as several derived products such as potential temperature and relative humidity.

Brown, Shannon T.↗
NASA NTRS1985

Lidar profiling of thermodynamic properties of the atmosphere

Principles and applications of pulsed laser methods for temperature, pressure, density, and humidity measurements in the altitude range 0-100 km are discussed. The differential absorption lidar (DIAL) method requires that at least one of the transmitted laser pulses be carefully tuned onto an absorption feature of the species, whereas Raman backscatter methods do not require tunability. OH and Na fluorescence require tuning of the excitation, and are the most suitable methods for high altitude where the atomic and molecular reemission is relatively unquenched by collisions.

Wilkerson, T. D.↗
NASA NTRS1980

Refraction of microwave signals by water vapor

Tropospheric water vapor causes a refractive path length effect which is typically 5-10% of the 'dry' tropospheric effect and as large as several meters at elevation angles below 5 deg. The vertical water vapor profile is quite variable, and measurements of intensive atmospheric parameters such as temperature and humidity limited to the surface do not adequately predict the refractive effect. It is suggested that a water vapor refraction model that is a function of the amount of precipitable water alone can be successful at low elevation angles. From an extensive study of numerical ray tracings through radiosonde balloon data, such a model has been constructed. The model predicts the effect at all latitudes and elevation angles between 2 and 10 deg to an accuracy of better than 4% (11 cm at 3 deg elevation angle).

Goldfinger, A. D.↗
NASA NTRS2015

Advancement of Miniature Optic Gas Sensor (MOGS) Probe Technology

Advancement of Miniature Optic Gas Sensor (MOGS) Probe Technology" project will investigate newly developed optic gas sensors delivered from a Small Business Innovative Research (SBIR) Phase II effort. A ventilation test rig will be designed and fabricated to test the sensors while integrated with a Suited Manikin Test Apparatus (SMTA). Once the sensors are integrated, a series of test points will be completed to verify that the sensors can withstand Advanced Suit Portable Life Support System (PLSS) environments and associated human metabolic profiles for changes in pressure and levels of Oxygen (ppO2), carbon dioxide (ppCO2), and humidity (ppH2O).

Chullen, Cinda↗
NASA NTRS2005

Impact of CAMEX-4 Data Sets for Hurricane Forecasts using a Global Model

This study explores the impact on hurricane data assimilation and forecasts from the use of dropsondes and remote-sensed moisture profiles from the airborne Lidar Atmospheric Sensing Experiment (LASE) system. We show that the use of these additional data sets, above those from the conventional world weather watch, has a positive impact on hurricane predictions. The forecast tracks and intensity from the experiments show a marked improvement compared to the control experiment where such data sets were excluded. A study of the moisture budget in these hurricanes showed enhanced evaporation and precipitation over the storm area. This resulted in these data sets making a large impact on the estimate of mass convergence and moisture fluxes, which were much smaller in the control runs. Overall this study points to the importance of high vertical resolution humidity data sets for improved model results. We note that the forecast impact from the moisture profiling data sets for some of the storms is even larger than the impact from the use of dropwindsonde based winds.

Kamineni, Rupa↗
NASA NTRS1993

Tropospheric gas composition and cloud structure of the Jovian North Equatorial Belt

Voyager IRIS observations of the NEB reveal longitudinal variability of 5-micron brightness temperatures of order 100 C. An anisotropic multiple scattering radiative transfer model is used to calculate synthetic spectra for comparison with the IRIS observations. Mie theory is used to model the spectral dependence of cloud extinction from 180 to 2300/cm. Cloud base locations within the model vary with assumed gas abundances according to thermochemical equilibrium. It is found that spatial variations in the abundance profiles of the condensible species, parahydrogen profiles and cloud optical depths can be used as tracers of the local and large-scale dynamics. The variation of cloud opacity is strongly correlated with the variation of relative humidity, which suggests that dynamic depletion of water vapor above the cloud forming level is the most plausible model to explain the spatial variation in the water profile within the NEB.

Carlson, Barbara E.↗
NASA NTRS1992

Water vapor profiling over ocean surface with 90 GHz and 183 GHz measurements under clear and cloudy conditions

Radiometric measurements at 90 GHz and three sideband frequencies near the peak water vapor absorption line of 183.3 GHz were made with the Advanced Microwave Moisture Sounder (AMMS) aboard the NASA DC-8 aircraft over some regions of the Pacific Ocean. These measurements were used to retrieve atmospheric water vapor profiles over ocean surface using the algorithm developed by Schaerer and Wilheit (1979). The algorithm incorporates a mechanism to estimate cloud liquid water when the estimated relative humidity is greater than 95 percent. The results are compared with estimated values from measurements taken by the Special Sensor Microwave/Imager (SSMI) and TIROS Operational Vertical Sounder (TOVS). The water vapor profiles estimated from AMMS are generally higher at low altitudes and lower at high altitudes than those from the TOVS measurements. Cloud liquid water is retrieved from both AMMS and SSM/I measurements over the same general regions. The retrieved water vapor profiles show more fluctuations in these regions. It is concluded that the AMMS with only four channels of measurements may not be able to retrieve both water vapor and cloud information with authority.

Wang, J. R.↗
NASA NTRS1971

Combustion of a premixed system in stagnation flow. I - Theoretical.

The theoretical steady-state and transient characteristics of a premixed combustible system in laminar axisymmetric stagnation flow are studied by way of numerical solution of the governing boundary-layer equations. Computations, which are based on the oxidation reaction of carbon monoxide in humid air, invoke a minimum of simplifying assumptions. Steady-state results include prediction of (1) profiles of the state variables, (2) extinction of blow-off conditions, (3) ignition conditions, and (4) the heat flux to the stagnation point. Computer simulations of the unsteady state provide an indication of the stability of a given steady state to perturbations. Comparisons between some of the predictions of the mathematical model and the results of laboratory experiments will be reported in Part II.

Smith, H. W.↗
NASA NTRSDate not supplied

International Satellite Cloud Climatology Project (ISCCP) TIROS Operational Vertical Sounder (TOVS) Product in Native (NAT) Format (ISCCP_TOVS_NAT)

Since 1983 an international group of institutions has collected and analyzed satellite radiance measurements from up to five geostationary and two polar orbiting satellites to infer the global distribution of cloud properties and their diurnal, seasonal and interannual variations. The primary focus of the first phase of the project (1983-1995) was the elucidation of the role of clouds in the radiation budget (top of the atmosphere and surface). In the second phase of the project (1995 onwards) the analysis also concerns improving understanding of clouds in the global hydrological cycle. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1983-07-01; Stop_Date=] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=280 degree; Longitude_Resolution=280 degree; Temporal_Resolution=Daily - < Monthly].

PRECIPITABLE WATER PROFILES↗
NASA NTRS2005

Influence of Nucleation Mechanisms on the Radiative Properties of Deep Convective Clouds and Subvisible Cirrus in CRYSTAL/FACE

During the past few years we have conducted work on several different topics, as reflected by our publications. As one of the Co-Project scientists for The Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL FACE) we worked to help design the mission and then conduct it in the field. Another major activity during the past two years has been to pull together various groups to formulate plans for follow on missions to CRYSTAL FACE. We organized a workshop at the University of Colorado during the summer of 2003 to assess the best locations for future missions. Working with a group of about 10 scientists from around the country we prepared a science-planning document (Tropical Composition, Cloud and Climate Coupling Experiment (TC(sup 4)) that outlined the rationale, locations, strategy to accomplish the goals, and possible payloads for a set of three tropical missions. We also prepared background materials for various NRAs being prepared at NASA Headquarters for missions in Costa Rica, Darwin and Guam. In conjunction with the group at NASA Ames we have helped build a new numerical model for deep convection and have applied that model to simulate the CRYSTAL data. Our goal in particular has been to better understand how convection distributes water vapor isotopes. CRYSTAL observations of water isotopes are very different from those suggested by previous workers who assumed the isotopes would obey Rayleigh fractionation. The water isotope study has several implications. First it is a check on the realism of the deep convection model. Second, the isotopes are a measure of the precipitation removal in the atmosphere. Hence they provide a constraint on a parameter that is difficult to otherwise measure. Finally it has been suggested that isotopes may be the key to unraveling the water transport into the stratosphere and upper troposphere. Such transport is critical both for the radiation balance and for stratospheric chemistry. Ours is the first model that is able to treat this transport. Our initial results have just been submitted to Geophys. Res. Lett (Smith et al., 2005). Essentially we are able to explain the vertical profiles of isotopes in the tropical tropopause transition layer. We are also able to account for stratospheric humidity and isotope abundances with this model. We have also been heavily involved in trying to improve our understanding of nitric acid condensation on ice. Gao et al (2004) have shown that water supersaturations above ice occur when the atmosphere is supersaturated with respect to nitric acid trihydrate. As one of the co-authors of that work, we suggested the mechanism that may explain why this is occurring. Essentially, ice does not like to grow near unit supersaturation, but does so because the water molecules can find sites on the ice surface to attach themselves to before they fly off the ice surface. This phenomena was well known in the 1960s when it was a source of debate about whether condensation and evaporation coefficients for ice would be the same. Evaporation does not require any molecular orientation, while condensation does, so it was possible that the coefficients would differ. They don't differ because the water molecules rapidly move across the surface and find places to attach. Nitric acid may be occupying these preferred sites and therefore the water molecules can't find a desirable place to attach. We anticipate that this research will be the subject of laboratory work during the coming few years. Another possibility that has been suggested is that cubic ice is forming in clouds. We have measured the vapor pressure of cubic ice, and plan to publish that result in the next few months. We have also been working on additional aspects of the condensation of nitric acid on ice. With Y. Kondo we studied the condensation of NOy on ice using the SOLVE data. Gamblin et al. have continued this work. The CRYSTAL NOy and HNO, groups have shown th their data can be fit using standard Langmuir isotherms as suggested in some, but not all, laboratory studies. We have found in the SOLVE data set that this is not the case. Moreover some laboratory studies show there are important kinetic effects that may be occurring in the atmosphere limiting the transfer of nitric acid to the ice. The SOLVE data seem consistent with these studies. We are currently re-analyzing the CRYSTAL data to look for these kinetic effects. There are a number of implications of these studies. One of the more interesting is that the nitric acid coating on ice can be used as a cloud clock to determine how long the cloud parcel has been in existence. We have also been involved with several laboratory studies. We have worked to improve the database on ice optical constants, which are critical for remote sensing. We have also studied the ways in which ice nucleates on clays. We suspect now that the standard theories used for depositional ice nucleation are completely incorrect. Further work will be needed to develop a new theory.

Toon, Owen B.↗
NASA NTRS2005

Models for Water Isotopes Constrained with Data from Crystal Face

During the year covered by this proposal we conducted work on several different topics, as reflected by our publications listed below. One major activity was to work with a group of about 10 scientists from around the country to prepare a science-planning document (Tropical Composition, Cloud and Climate Coupling Experiment (TC4)) that outlined the rationale, locations, strategy to accomplish the goals, and possible payloads for a set of three tropical missions. We also prepared background materials for various NRAs being prepared at NASA Headquarters for missions in Costa Rica, Darwin and Guam. Unfortunately budgetary constraints prevented these missions from moving forward. In conjunction with the group NASA Ames we built a new numerical model for deep convection and have applied that model to simulate the CRYSTAL isotope data. Our goal in particular has been to better understanding how convection distributes water vapor isotopes. CRYSTAL observations of water isotopes are very different from those suggested by previous workers who assumed the isotopes would obey Rayleigh fractionation. The water isotope study has several implications. First it is a check on the realism of the deep convection model. Second, the isotopes are a measure of the precipitation removal in the atmosphere. Hence they provide a constraint on a parameter that is difficult to otherwise measure. Finally it has been suggested that isotopes may be the key to unraveling the water transport into the stratosphere and upper troposphere. Such transport is critical both for the radiation balance and for stratospheric chemistry. Ours is the first model that is able to treat this transport. Our initial results are now in press in Geophys. Res. Lett. Essentially we are able to explain the vertical profiles of isotopes in the tropical tropopause transition layer. We are also able to account for stratospheric humidity ana isotope abundances with this model. The data suggest that isotopes do not provide a clear constraint on the mechanism by which water enters the stratosphere- whether by convection, or by slow ascent. Our work is relevant for the water isotope comparison experiments recently done by NASA. We are conducting numerical experiments related to this project to help understand that data.

Toon, Owen B.↗
NASA NTRS2003

An Analysis of the Automated Meteorological Profiling System Low Resolution Flight Element

A study was conducted to determine the quality of thermodynamic and wind data measured by or derived from the Low Resolution Flight Element (LRFE) of the Automated Meteorological Profiling System (AMPS). The AMPS LRFE replaced the Meteorological Sounding System (MSS), which was used to provide vertical profiles of thermodynamic and low-resolution wind data in support of spacecraft launch operations at the Cape Canaveral Air Force Station (CCAFS) and NASA Kennedy Space Center (KSC), Florida. Air temperature, relative humidity, and height, which are directly measured by the LRFE, are used to derive air pressure and density. Test flights were conducted where an LRFE sonde and an MSS sonde were attached to the same balloon and the two profiles were compared. MSS data was used as the standard reference data. The objective of the thermodynamic testing was to determine a) if the LRFE met Space Shuttle Program (SSP) accuracy requirements outlined in the Space Shuttle Launch and Landing Program Requirements Document (PRD) and/or, b) if the LRFE met or exceeded MSS data quality. AMPS uses the Global Positioning System (GPS) to determine wind speed and direction. In order to provide a basis for comparison, either an AMPS High Resolution Flight Element (HRFE) or a radar tracked Jimsphere was released simultaneously with each AMPS LRFE at CCAFS. The goal of these tests was to determine if the LRFE wind data met the requirement for low-resolution wind data defined in the Shuttle PRD. Based on the available data, the LRFE is shown to produce more consistent thermodynamic measurements than the MSS. The LRFE is also shown to meet the Shuttle PRD requirements for low resolution wind data.

Leahy, Frank B.↗
NASA NTRS2014

Horizontal Variability of Water and Its Relationship to Cloud Fraction near the Tropical Tropopause: Using Aircraft Observations of Water Vapor to Improve the Representation of Grid-scale Cloud Formation in GEOS-5

Large-scale models such as GEOS-5 typically calculate grid-scale fractional cloudiness through a PDF parameterization of the sub-gridscale distribution of specific humidity. The GEOS-5 moisture routine uses a simple rectangular PDF varying in height that follows a tanh profile. While below 10 km this profile is informed by moisture information from the AIRS instrument, there is relatively little empirical basis for the profile above that level. ATTREX provides an opportunity to refine the profile using estimates of the horizontal variability of measurements of water vapor, total water and ice particles from the Global Hawk aircraft at or near the tropopause. These measurements will be compared with estimates of large-scale cloud fraction from CALIPSO and lidar retrievals from the CPL on the aircraft. We will use the variability measurements to perform studies of the sensitivity of the GEOS-5 cloud-fraction to various modifications to the PDF shape and to its vertical profile.

climate modeling↗
NASA NTRS2003

Evaluation of the Space Shuttle Transatlantic Abort Landing Atmospheric Sounding System

A study was conducted to determine the quality of thermodynamic and wind data measured by or derived from the Transatlantic Abort Landing (TAL) Atmospheric Sounding System (TASS). The system has Global Positioning System (GPS) tracking capability and includes a helium-filled latex balloon that carries an instrument package (sonde) and various ground equipment that receives and processes the data from the sonde. TASS is used to provide vertical profiles of thermodynamic and low-resolution wind data in support of Shuttle abort landing operations at TAL sites. TASS uses GPS to determine height, wind speed, and wind direction. The TASS sonde has sensors that directly measure air temperature and relative humidity. These are then used to derive air pressure and density. Test flights were conducted where a TASS sonde and a reference sonde were attached to the same balloon and the two profiles were compared. The objective of the testing was to determine if TASS thermodynamic and wind data met Space Shuttle Program (SSP) accuracy requirements outlined in the Space Shuttle Launch and Landing Program Requirements Document (PRD).

Leahy, Frank B.↗
NASA NTRS1988

High-resolution Interferometer Sounder (HIS), phase 2

The High-resolution Interferometer Sounder (HIS) was successfully built, tested, and flight proven on the NASA U-2/ER-2 high altitude aircraft. The HIS demonstration has shown that, by using the technology of Fourier Transform Spectroscopy (FTS), it is possible to measure the spectrum of upwelling infrared radiance needed for temperature and humidity sounding with high spectral resolution and high radiometric precision. By resolving individual carbon dioxide lines, the retrieved temperature profiles have vertical resolutions of 1 to 2 km and RMS errors less than 1 C, about 2 to 4 times better than possible with current sounders. Implementing this capability on satellite sounders will greatly enhance the dynamical information content of temperature measurements from space. The aircraft model HIS is now a resource which should be used to support field experiments in mesoscale meteorology, to monitor trace gas concentrations and to better understand their effects on climate, to monitor the surface radiation budget and the radiative effects of clouds, and to collect data for research into retrieval techniques, especially under partially cloudy conditions.

Source record↗