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Ellis Remsberg

Publications and source records attributed to Ellis Remsberg.

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

An Assessment of Stratospheric Water Vapor Trends and Variations Above the Boulder Region

This study analyzes time series of stratospheric water vapor (SWV) data at 30 hPa, based on frost-point hygrometer (FPH) measurements at Boulder, CO (40°N, 255°E), and on sets of HALOE scans above that region for 1993 through 2005; their differing trends agree with previously published findings. Yet, there is an apparent switch over in 2002 from positive to negative trends in the HALOE time series, and that change follows the episodic decrease of tropical, lower stratospheric SWV in early 2001. The HALOE data points only resolve medium to large scale spatial variations, as they are based on an average of four or more limb scans within a latitude/longitude sector near Boulder. The FPH time series do not indicate a similar change of trend in 2002, although its time series points have variations about the mean that are twice as large as those from HALOE. The FPH soundings are sensitive to variations from all spatial scales, however, including the effects of a local vertical mixing of the air due to gravity waves. The vertical gradient SWV mixing ratio with altitude is positive at 30 hPa. There is also a positive trend in methane and its conversion to water vapor during this time that may explain a slightly larger SWV trend from the local FPH data than from the HALOE data. The Nimbus 7 LIMS experiment provides daily SWV plots at medium to large scales during the dynamically active, winter and springtime periods, for assessing the effects of meridional transport of SWV from its source regions. There is transport of high SWV from polar regions and of lower SWV from the subtropics at those times. SWV variations and trends from both the FPH and HALOE time series are reasonable and in accord with the spatial scales that they observed.

Ellis Remsberg↗
NASA NTRS2021

Residual Temperature Bias Effects in Stratospheric Species Distributions from LIMS

The Nimbus 7 Limb Infrared Monitor of theStratosphere (LIMS) instrument operated from 25 Octo-ber 1978 through 28 May 1979. Its version 6 (V6) profileswere processed and archived in 2002. We present severaldiagnostic examples of the quality of the V6 stratospheric species distributions based on their level 3 zonal Fourier co-efficient products. In particular, we show that there are smalldifferences in the ascending (A) minus descending (D) or-bital temperature–pressure orT(p) profiles (theirA−Dval-ues) that affect (A−D) species values. SystematicA−Dbi-ases inT(p) can arise from small radiance biases and/or fromviewing anomalies along orbits. There can also be (A−D)differences inT(p) due to not resolving and correcting forall of the atmospheric temperature gradient along LIMS tan-gent view-paths. An error inT(p) affects species retrievalsthrough (1) the Planck blackbody function in forward calcu-lations of limb radiance that are part of the iterative retrievalalgorithm of LIMS, and (2) the registration of the measuredLIMS species radiance profiles in pressure altitude, mainlyfor the lower stratosphere. There are clearA−Ddifferencesfor ozone, H2O, and HNO3but not for NO2. Percentage differences are larger in the lower stratosphere for ozone andH2O because those species are optically thick. We evaluateV6 ozone profile biases in the upper stratosphere with the aid of comparisons against a monthly climatology of UV–ozone soundings from rocketsondes. We also provide resultsof time series analyses of V6 ozone, H2O, and potential vor-ticity for the middle stratosphere to show that their average(A+D) V6 level 3 products provide a clear picture of the evolution of those tracers during Northern Hemisphere win-ter. We recommend that researchers use the average V6 level3 product for their science studies of stratospheric ozone andH2O, while keeping in mind that there are uncorrected non-local thermodynamic equilibrium effects in daytime ozone inthe lower mesosphere and in daytime H2O in the uppermoststratosphere. We also point out that the present-day Soundingof the Atmosphere using Broadband Emission Radiometry(SABER) experiment provides measurements and retrievalsof temperature and ozone that are nearly free of anomalousdiurnal variations and of effects from gradients at low and middle latitudes.

Ellis Remsberg↗
NASA NTRSDate not supplied

TPSAS-NF1676L-11998-DND

By 1971 the National Aeronautics and Space Administration (NASA) was beginning to phase down its Apollo Moon Program in favor of developing a partly reusable Space Shuttle vehicle that could be used to construct and supply a manned, Earth-orbiting Space Station. In 1970 an international report of the Study of Critical Environmental Problems (SCEP) had been issued by the MIT Press. Thus, the Agency began to emphasize its Space Applications programs in response to the growing public concern about Earth?s finite natural resources and the degradation of its environment. Shortly thereafter, a NASA workshop was convened in Norfolk, Virginia, on the topic of the Remote Measurement of Pollution (or RMOP), and its findings can be found in a NASA Special Publication (NASA SP-285, 1971). Its three primary panels and their chairmen were focused on trace gas species (Will Kellogg), atmospheric particulates or aerosols (Verner Suomi), and water pollution (Gifford Ewing). Many of the workshop participants were specialists in the techniques that might be employed for the regional to global-scale, remote measurements of pollution from an Earth-orbiting satellite. In fact, the findings and recommendations of the SCEP and RMOP Reports represent the genesis of and blueprint for the satellite Earth-sensing programs within NASA for the following several decades. This paper is a brief, 40-year retrospective of the instrument developments and demonstrated measurement successes for temperature and gaseous species that were an outgrowth of the RMOP activity.

Ellis Remsberg↗
NASA NTRSDate not supplied

On Dynamical Impacts on Stratospheric Water Vapor Trends Above Boulder, Colorado

Long-term stratospheric water vapor (SWV) trends above Boulder, CO, (40°N, 255°E) are generally positive and slightly larger than those for zonal average SWV. This study finds a slight enhancement for SWV at 31.6 hPa above Boulder from middle February through March 1979, as seen in the satellite dataset from the LIMS instrument. That excess of SWV correlates well with air in the polar vortex that underwent an elongation and splitting in middle February following a final stratospheric warming event. Zonal wave-2 events tend to occur in late winter, but not every year. Such aperiodic variations in data time series of SWV may affect the fitting of its linear trend term.

Ellis Remsberg↗
NASA NTRSDate not supplied

On Dynamical Impacts on Stratospheric Water Vapor Trends Above Boulder, Colorado

Long-term stratospheric water vapor (SWV) trends above Boulder, CO, (40°N, 255°E) are generally positive and slightly larger than those for zonal average SWV. This study finds a slight enhancement for SWV at 31.6 hPa above Boulder from middle February through March 1979, as seen in the satellite dataset from the LIMS instrument. That excess of SWV correlates well with air in the polar vortex that underwent an elongation and splitting in middle February following a final stratospheric warming event. Zonal wave-2 events tend to occur in late winter, but not every year. Such aperiodic variations in data time series of SWV may affect the fitting of its linear trend term.

Ellis Remsberg↗