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At least 19 records

Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) Antarctic ozone atlas: August through November 1991

Because of the great environmental significance of stratospheric ozone, and to support continuing research at the Antarctic Southern Hemisphere stations, the development of the 1991 ozone hole was monitored using data from the Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) instrument, produced in near-real-time. This atlas provides a complete set of daily polar orthographic projections of the TOMS total ozone measurements over the Southern Hemisphere for the period August 1 through November 30, 1991. The 1991 ozone hole developed in a manner similar to that of the 1987, 1989, and 1990 holes, reaching a comparable depth in early October. However, the 1991 ozone hole filled far more rapidly than in 1987 or 1989, and nearly 4 weeks earlier than in 1990.

Krueger, Arlin J.↗

Evidence of Stratosphere-to-Troposphere Transport Within a Mesoscale Model and Total Ozone Mapping Spectrometer Total Ozone

We evaluate evidence for stratospheric mass transport into, and mass remaining in, the troposphere during an intense midlatitude cyclone. Mesoscale forecast model analysis fields from the Mesoscale Analysis and Prediction System were matched with total ozone observations from the Total Ozone Measurement Spectrometer. Combined with parcel back trajectory calculations, the analyses imply that two mechanisms contributed to the mass exchange: (1) An area of dynamically induced exchange was observed on the cyclone's southern edge. Parcels originally in the stratosphere crossed the jet core and were diluted through turbulent mixing with tropospheric air; (2) Diabetic effects reduced parcel potential vorticity (PC) for trajectories traversing precipitation regions, creating a 'PV hole' signature in the center of the cyclone. Air with characteristics of ozone and water vapor found in the lower stratosphere remained in the troposphere. The strength of the latter process may be unusual. Combined with other research, these results suggest that precipitation-induced diabetic effects can significantly modify (either decreasing or increasing) parcel potential vorticity, depending on parcel trajectory configuration with respect to maximum heating regions and jet core. The diabetic heating effect on stratosphere-troposphere exchange (STE) is more important to tropopause erosion than to altering parcel trajectories. In addition, these results underline the importance of using not only PC but also chemical constituents for diagnoses of STE.

Olsen, Mark A.↗

Meteor 3/total ozone mapping spectrometer observations of the 1993 ozone hole

The development of the springtime (September-November) Antarctic ozone hole was observed by the Meteor 3/total ozone mapping spectromter (TOMS) to result in the lowest ozone value, 85 DU (Dobson units) on October 8, 1993, ever measured by TOMS. During late September and early October the region of extremely low ozone values was centered on the geographical pole between 85 deg S and 90 deg S. The geographical extent of the ozone hole region, the area within the 220-DU contour, reached a maximum during the first week in October at a near-circular area covering 24 x 10(exp 6) sq km reaching to the southern tip of South America. This approximately matched the 1992 area record. After the maximum area was reached in early October, the 1993 ozone hole region was significantly larger than during 1992 throughout the remainder of the month of October. The very low ozone values over the Antarctic continent have been confirmed by independent ground-based data. Unlike 1992, the formation of the 1993 Antarctic ozone hole does not coincide with unusually low ozone values observed over most of the globe for the past 2 years. The most recent ozone data from Meteor 3/TOMS show that there has been a recovery at all latitudes from the extraordinarily low values observed during 1992 and part of 1993 after the June 1991 eruption of Mount Pinatubo. Meteor 3/TOMS is described and compared with Nimbus 7/TOMS during the 1991 to May 1993 overlap period. Observations of the 1992 ozone hole are presented from both instruments and are shown to agree within 5 DU.

Herman, J. R.↗

Comparison of Tropical Ozone from SHADOZ with Remote Sensing Retrievals from Suomi-npp Ozone Mapping Profile Suite (OMPS)

The Ozone Mapping Profile Suite (OMPS) was launched October 28, 2011 on-board the Suomi NPP satellite (http://npp.gsfc.nasa.gov). OMPS is the next generation total column ozone mapping instrument for monitoring the global distribution of stratospheric ozone. OMPS includes a limb profiler to measure the vertical structure of stratosphere ozone down to the mid-troposphere. This study uses tropical ozonesonde profile measurements from the Southern Hemisphere Additional Ozonesondes (SHADOZ, http://croc.gsfc.nasa.gov/shadoz) archive to evaluate total column ozone retrievals from OMPS and concurrent measurements from the Aura Ozone Monitoring Instrument (OMI), the predecessor of OMPS with a data record going back to 2004. We include ten SHADOZ stations that contain data overlapping the OMPS time period (2012-2013). This study capitalizes on the ozone profile measurements from SHADOZ to evaluate OMPS limb profile retrievals. Finally, we use SHADOZ sondes and OMPS retrievals to examine the agreement with the GEOS-5 Ozone Assimilation System (GOAS). The GOAS uses data from the OMI and the Microwave Limb Sounder (MLS) to constrain the total column and stratospheric profiles of ozone. The most recent version of the assimilation system is well constrained to the total column compared with SHADOZ ozonesonde data.

OMPS↗

New Total Ozone Algorithm for Application to the Total Ozone Mapping Spectrometer

The Total Ozone Mapping Spectrometer (TOMS) series comprises four instruments providing a total of 25 years of daily global stratospheric ozone data over the sunlit portion of the Earth. A new retrieval algorithm has been developed for TOMS, designated Version 8. The algorithm is based on differential absorption across a pair of wavelength channels chosen close together to minimize the impact of wavelength dependent forward modeling errors. Version 8 enhancements include correction for the presence of tropospheric aerosols and sun glint from water surfaces, a better treatment of variability due to tropospheric ozone and temperature dependence, and an improved forward model, particularly in regions of persistent snow and ice. Among other things, the Version 8 enhancements have reduced latitudinal dependence seen previously in TOMS - Dobson comparisons, predominantly in the Southern Hemisphere's summer, when the tropospheric ozone, temperature, and snow/ice corrections are additive. The basic components of the algorithm and its impact on derived total ozone will be discussed.

Wellemeyer, C.↗

First results from the Nimbus 7 total ozone mapping spectrometer

The Total Ozone Mapping Spectrometer (TOMS) instrument was launched on the Nimbus 7 satellite in October 1978. This instrument is designed to measure spatial variations in the total ozone field. The employed technique is an extension of the Backscattered Ultraviolet (BUV) total ozone method. The TOMS instrument has an improved capability for detailed monitoring of total ozone. The obtained data appear to contain information about dynamical processes in the upper troposphere and the lower stratosphere. Investigations are being conducted to determine qualitatively the conditions, if any, where total ozone fails as a predictor for tropopause height. Quantitative relations between the dynamic parameters and total ozone are also being studied.

Krueger, A. J.↗

Nimbus 7 total ozone mapping spectrometer (TOMS) data during the Gap, France, ozone intercomparisons of June 1981

The Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) data over Europe have been processed for 2 days of the ozone sensor intercomparison balloon campaign in June 1981 at Gap, France. The June 19 TOMS map shows an elongated ozone maximum (about 400 D.U) extending in a NW-SE direction across central Europe and an ozone minimum (300 D.U.) in the central Atlantic. This pattern produces a 12 D.U. decrease along the balloon trajectory from the fist ascent to the second descent. On June 26 a much smaller ozone maximum (400 D.U.) is centered in northern France with its main axis running in a SW-NE direction. The total ozone contours tend to lie parallel to the balloon trajectory so that the total ozone during the flight is nearly constant.

Krueger, A. J.↗

Low ozone amounts during 1992 - 1993 from Nimbus 7 and Meteor 3 total ozone mapping spectrometers

The global distribution of ozone during the October 31, 1978, to May 6, 1993, observing lifetime of the Nimbus 7 total ozone mapping spectrometer (TOMS) is described, with emphasis on the low ozone amounts observed during 1992 and 1993. Ozone amount time series are extended beyong May 6, 1993, to the end of July 1993 using preliminary Meteor 3 TOMS data. Time series for zonally averaged ozone amounts show that there has not been a significant shift in the seasonal patterns of ozone maxima and minima caused by the Mount Pinatubo eruption or by the onset of very low ozone values during 1992 and 1993. There has been a relatively slow, nearly linear decrease in the amount of ozone over the entire globe from 1979 to the end of 1991, with rates ranging from no change at the equator to a 4 - 6% decrease per decade at midlatitudes and a 10 - 12% decrease per decade at higher latitudes. After the eruption of Mount Pinatubo during June 1991, the ozone amount decreased in the equatorial latitudes (10 deg S to 10 deg N) for about 6 months (-10 Dobson units (DU) between 0 deg and 10 deg S and -3 DU between 0 deg and 10 deg N). During 1992 and continuing into 1993, the rate of ozone decrease deviated from the previously linear trend with the onset of changes that were large in comparison with the historical range of ozone values from 1979 to 1991. The first of the large decreases in ozone amount occurred earlier, in February 1990 to May 1990, at 50 deg - 70 deg N. At high northern latitudes, the 1993 decreased ozone amounts were about 12.5% below the envelope of historical values; at midlatitudes they were about 7% lower; and at low latitudes they were about 4% lower. Area-weighted averages in the northern and southern hemispheres show that most of the 1992 - 1993 ozone losses have occurred in the northern hemisphere. The 1993 global average (70 deg S to 70 deg N) ozone amount is 3% below the 1979 to 1991 minimum, 5% below the historical envelope in the northern hemisphere, and near the lower boundary of the historical envelope in the southern hemisphere. In the 70 deg - 60 deg S latitude band, the ozone losses between 1979 and 1993 have reduced the annual minimum amount to values below those seen in the equatorial regions.

Herman, J. R.↗

Expected Performance of Ozone Climate Data Records from Ozone Mapping and Profiler Suite Limb Profiler

The Ozone Mapping and Profiler Suite Limb Profiler (OMPS/LP) was launched on board of the Soumi NPP space platform in late October 2011. It provides ozone-profiling capability with high-vertical resolution from 60 Ian to cloud top. In this study, an end-to-end Observing System Simulation Experiment (OSSE) of OMPS/LP ozone is discussed. The OSSE was developed at NASA's Global Modeling and Assimilation Office (GMAO) using the Goddard Earth Observing System (GEOS-5) data assimilation system. The "truth" for this OSSE is built by assimilating MLS profiles and OMI ozone columns, which is known to produce realistic three-dimensional ozone fields in the stratosphere and upper troposphere. OMPS/LP radiances were computed at tangent points computed by an appropriate orbital model. The OMPS/LP forward RT model, Instrument Models (IMs) and EDR retrieval model were introduced and pseudo-observations derived. The resultant synthetic OMPS/LP observations were evaluated against the "truth" and subsequently these observations were assimilated into GEOS-5. Comparison of this assimilated dataset with the "truth" enables comparisons of the likely uncertainties in 3-D analyses of OMPS/LP data. This study demonstrated the assimilation capabilities of OMPS/LP ozone in GEOS-5, with the monthly, zonal mean (O-A) smaller than 0.02ppmv at all levels, the nns(O-A) close to O.lppmv from 100hPa to 0.2hPa; and the mean(O-B) around the 0.02ppmv for all levels. The monthly zonal mean analysis generally agrees to within 2% of the truth, with larger differences of 2-4% (0.1-0.2ppmv) around 10hPa close to North Pole and in the tropical tropopause region, where the difference is above 20% due to the very low ozone concentrations. These OSSEs demonstrated that, within a single data assimilation system and the assumption that assimilated MLS observations provide a true rendition of the stratosphere, the OMPS/LP ozone data are likely to produce accurate analyses through much of the stratosphere. Additional studies are needed to evaluate the importance of the extremely high vertical resolution of the OMPS/LP ozone data

Xu, P. Q.↗

Joint Assimilation of the Aura Microwave Limb Sounder and Ozone Mapping and Profiler Suite Limb Profiler Data: Towards a Reanalysis of Stratospheric Ozone for Trend Studies

The future trajectory of the stratospheric ozone recovery will be sensitive to greenhouse gas concentrations through thermal control of chemical loss and via stratospheric circulation changes. The latter in particular is subject to considerable uncertainty meriting continuing monitoring of the evolution of ozone throughout the depth of the stratosphere. Atmospheric reanalyses utilize the data assimilation methodology to obtain comprehensive representations of the state of the atmosphere, including its composition, on multidecadal scales by combining diverse measurements from satellite-borne and conventional data sources. Systematic biases among these various data types pose a challenge for assimilation by introducing spurious discontinuities that affect the utility of reanalyses for studies of long-term variability and trends.In this presentation we will outline an approach, developed at NASA's Global Modeling and Assimilation Office (GMAO), that allows joint assimilation of stratospheric ozone profiles from the Microwave Limb Sounder (MLS) on EOS Aura and the Ozone Mapping and Profiler Suite Limb Profiler (OMPS-LP) currently flying on the Suomi-NPP satellite with future missions projected into the 2030s. We will demonstrate that a simple offline correction significantly reduces biases between MLS and OMPS-LP ozone data providing a strategy for generating a long-term vertically resolved homogenized representation of stratospheric ozone in future reanalyses. One novel element of our approach compared to previous GMAO reanalysis is the use of a version of the Goddard Earth Observing System model with full stratospheric chemistry. We will show selected comparisons of MLS and OMPS-LP assimilation experiments with independent ozonesonde and satellite data as well as two examples of process-based evaluation focused on the 2016 QBO disruption and Arctic winter ozone loss focusing on the relative performance of the MLS and OMPS-LP analyses.

Wargan, K.↗

A global climatology of total ozone from the Nimbus 7 total ozone mapping spectrometer

A global climatology of total column ozone has been computed from 4 years of daily observations by the total ozone mapping spectrometer aboard the Nimbus 7 polar-orbiting satellite. Observations were made at local noon; no observations are available in polar regions during the polar night. The orbital data have been area averaged onto a regular 5 deg by 5 deg latitude-longitude grid. The global coverage is more than 90 percent complete during the last 3 observing years (October 1979 to September 1982) and approximately 70 percent complete during the first year (October 1978 to September 1979). Global maps of the temporal mean and rms variance and the amplitude and phase of the annual and semiannual harmonics are presented. Similar analyses of the zonal mean values are given along with a time-latitude section of the zonal-mean total ozone. This climatology should be useful both for validating numerical models and for inspiring theoretical analyses.

Bowman, K. P.↗

Results from the US/Russian Meteor-3/Total Ozone Mapping Spectrometer

The development of Meteor-3/TOMS (Total Ozone Mapping Spectrometer) was a joint project of the United States and Russia to fly a U.S. ozone measuring instrument (TOMS) onboard a Russian spacecraft (Meteor-3) and rocket (Cyclone), launched from Plesetsk, Russia. The Meteor-3/TOMS (M3TOMS) was launched into a 1202-km-high, near-polar orbit on 15 Aug. 1991, where it can obtain complete global coverage for most of each year. Both the U.S. and Russian sides have successfully received and processed data into ozone amounts from 25 Aug. 1991 to 1 Jun. 1992, and expect to continue for the life of the instrument and spacecraft. The successful development of the instrument hardware, spacecraft interface, data memory, telemetry systems, and software are described. Descriptions are given of the U.S. and Russian ground stations for receiving M3TOMS data. In addition, the data reduction software was independently developed by the U.S. and by the Russians, and is shown to agree to better than the precision of the measurements.

Herman, Jay R.↗

Tropospheric Ozone Pollution from Space: New Views from the TOMS (Total Ozone Mapping Spectrometer) Instrument

New products from the TOMS (Total Ozone Mapping Spectrometer) >satellite instrument can resolve pollution events in tropical and mid-latitudes, Over the past several years, we have developed tropospheric ozone data sets by two methods. The modified-residual technique [Hudson and Thompson, 1998; Thompson and Hudson, 1999] uses v. 7 TOMS total ozone and is applicable to tropical regimes in which the wave-one pattern in total ozone is observed. The TOMSdirect method [Hudson et at., 2000] represents a new algorithm that uses TOMS radiances to extract tropospheric ozone in regions of constant stratospheric ozone and tropospheric ozone displaying high mixing ratios and variability characteristic of pollution, Absorbing aerosols (dust and smoke; Herman et at., 1997 Hsu et al., 1999), a standard TOMS product, provide transport and/or source marker information to interpret tropospheric ozone. For the Nimbus 7/TOMS observing period (1979-1992), modified-residual TTO (tropical tropospheric ozone) appears as two maps/month at I-degree latitude 2-degree longitude resolution at a homepage and digital data are available (20S to 20N) by ftp at http://metosrv2. umd.edu/~tropo/ 14y_data.d. Preliminary modified-residual TTO data from the operational Earth-Probe/TOMS (1996- present) are posted in near-real-time at the same website. Analyses with the new tropospheric ozone and aerosol data are illustrated by the following (I)Signals in tropical tropospheric ozone column and smoke amount during ENSO (El Nino-Southern Oscillation) events, e.g. 1982-1983 and the intense ENSO induced biomass fires of 1997-1998 over the Indonesian region [Thompson et a[, 2000a, Thompson and Hudson, 1999]. (2) Trends in tropospheric ozone and smoke aerosols in various tropical regions (Atlantic, Pacific, Africa, Brazil). No significant trends were found for ozone from1980-1990 [Thompson and Hudson, 19991 although smoke aerosols increased during the period [Hsu et al.,1999]. (3) Temporal and spatial offsets ("paradoxes") in tropical tropospheric ozone and smoke aerosol in regions of greatest tropical biomass burning [Thompson et at., 1996;2000b]. (4) Trans-boundary pollution tracking. With an air parcel (trajectory) model, smoke aerosol and ozone and dust plumes can be tracked across oceans (e.g., Asia to North America; North America to Europe) and national boundaries, e.g. Indonesia to Singapore and Malaysia during the 1997 ENSO fires.

Thompson, Anne M.↗

Selection of optimum wavelengths for ozone mapping from satellites

Faced with conflicting requirements for measuring total ozone with the Solar Backscatter Ultraviolet Spectrometer/Total Ozone Mapping Spectrometer (SBUV/TOMS), a recommended strategy is to select three wavelengths: one at the peak of the ozone absorption cross section spectrum, another at a nearby minimum and a third wavelength that lies just outside the absorption spectrum. A pair formed using the first two wavelengths are then used under most observing conditions; another pair formed using the last two wavelengths are used near the terminator. There is no evidence that the use of additional wavelengths provides any benefit for measuring total ozone. Additional wavelengths, however, are necessary if other atmospheric species, such as SO sub 2, need to be measured.

Bhartia, P. K.↗

Contingency maneuver strategies for the Total Ozone Mapping Spectrometer-Earth Probe (TOMS-EP)

The Total Ozone Mapping Spectrometer-Earth Probe (TOMS-EP) is a polar-orbiting spacecraft designed to measure total ozone levels in the Earth's atmosphere. The nominal mission orbit is a 955-kilometer circular Sun-synchronous orbit with an ascending node mean local crossing time (MLT) between 11:02 a.m. and 11:25 a.m. These two mean local ascending node times constitute the boundaries of the MLT box for this mission. The MLT boundaries were chosen to maintain the Sun-to-Earth-to-vehicle orbit-normal (SVN) angle within a preselected set of seasonally independent boundaries. Because the SVN angle is seasonally dependent, but the MLT is not, contingency options for correcting the MLT of orbital states that fall outside of the required MLT range become time dependent. This paper focuses on contingency orbit adjustment strategies developed at the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) during the mission planning phase of TOMS-EP. Time-dependent delta-V strategies are presented for correcting mission orbit states lying outside of the MLT range. Typically, passive control of the MLT drift rate can be used to restore the orbit state to the required MLT before a seasonal violation of SVN angle constraints can occur. Passive control of the MLT drift rate is obtained through adjustment of the semimajor axis and/or the inclination. The time between initial arrival on orbit at an 'out-of-the box' MLT state and violation of the SVN angle constraints is always less than or equal to 1 year. The choice of which parameter(s) to adjust is dictated by the duration of this time period, the desired mission lifetime, the delta-V cost, and operational constraints.

Kestler, James↗

The Solar Backscatter Ultraviolet and Total Ozone Mapping Spectrometer /SBUV/TOMS/ for Nimbus G

The SBUV/TOMS measures the atmospheric ozone vertical profile and the solar ultraviolet spectrum, and provides a total ozone map by means of a mechanical scan across the Nimbus track. While the SBUV/TOMS instrument has noteworthy design features such as a state-of-the-art double monochromator and fixed optical components on a nonmetallic structure, its most significant characteristic is an optimum system design based on technology proven on the BUV instrument.

Heath, D. F.↗

Observation guidelines for a Total Ozone Mapping Spectrometer (TOMS) in geosynchronous orbit

The successful utilization of Total Ozone Mapping Spectrometer (TOMS) measurements in low Earth orbit for the analysis of rapidly changing events has led to the consideration of a TOMS in geosynchronous orbit. This orbit should allow for the selection of temporal and spatial resolutions that are specifically designed for these events, plus the flexibility of selecting different sized areas and pointing the sensor to focus on the most interesting events. Separate temporal and spatial resolution guidelines plus recommended areal coverage have been developed for tropical cyclones, jet streams, the interaction between strong convection and the environment, and the surveillance of volcanoes. It is also suggested that the most effective use of TOMS would be simultaneous flights with microwave and high spatial resolution infrared temperature profiles.

Shenk, William E.↗