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NASA NTRS2002

INTEX-NA: Intercontinental Chemical Transport Experiment - North America

INTEX-NA is an integrated atmospheric chemistry field experiment to be performed over North America using the NASA DC-8 and P-3B aircraft as its primary platforms. It seeks to understand the exchange of chemicals and aerosols between continents and the global troposphere. The constituents of interest are ozone and its precursors (hydrocarbons, NOX and HOX), aerosols, and the major greenhouse gases (CO2, CH4, N2O). INTEX-NA will provide the observational database needed to quantify inflow, outflow, and transformations of chemicals over North America. INTEX-NA is to be performed in two phases. Phase A will take place during the period of May-August 2004 and Phase B during March-June 2006. Phase A is in summer when photochemistry is most intense and climatic issues involving aerosols and carbon cycle are most pressing, and Phase B is in spring when Asian transport to North America is at its peak. INTEX-NA will coordinate its activities with concurrent measurement programs including satellites (e. g. Terra, Aura, Envisat), field activities undertaken by the North American Carbon Program (NACP), and other U.S. and international partners. However, it is being designed as a 'stand alone' mission such that its successful execution is not contingent on other programs. Synthesis of the ensemble of observation from surface, airborne, and space platforms, with the help of global/regional models is an important It is anticipated that approximately 175 flight hours for each of the aircraft (DC-8 and P-3B) will be required for each Phase. Principal operational sites are tentatively selected to be Bangor, ME; Wallops Island, VA; Seattle, WA; Rhinelander, WI; Lancaster, CA; and New Orleans, LA. These coastal and continental sites can support large missions and are suitable for INTEX-NA objectives. The experiment will be supported by forecasts from meteorological and chemical models, satellite observations, surface networks, and enhanced O3,-sonde releases. In addition to characterizing Atlantic-outflow and Pacific-inflow, INTEX-NA will characterize air masses transported between the U.S., Canada, and Mexico. INTEX-NA will be the first continental scale inflow, outflow, and transformation experiment to be performed over North America. It will provide the most comprehensive observational data set to date to understand the O3/NOX/HOX/aerosol photochemical system and the carbon cycle. One of the critical needs of the carbon cycle research is to obtain large-scale vertical and horizontal concentration gradients of CO2, throughout the troposphere over continental source/sink regions. INTEX-NA is ideally suited to perform this role. Coastal and continental operational sites will allow us to develop a curtain profile of greenhouse gases (e. g. CO2,) and other key pollutants across North America. Such information is central to our quantitative understanding of chemical budgets on the continental scale. We expect to provide a number of satellite under-flights over land and water to test and validate observations from the appropriate satellite platform (e. g. Aura). We plan to develop strong collaborations with other national and international observational programs. Results from INTEX-NA should directly benefit the development of environmental policy for air quality and climate change.

Singh, Hanwant B.↗
NASA NTRS1986

Moisture transports and budgets of 'moisture bursts'

The paper discusses moisture fluxes and budgets associated with a pair of 'moisture bursts' in the eastern North Pacific Ocean area, described by Smith et al. (1985). The moisture fluxes were calculated using data obtained during the first Special Observing Period (SOP-1) of the FGGE. The area specifically examined extended from the equator to the latitude 20 deg N and from longitude 180 deg to 100 deg W, with concentration on the region south and southeast of the Hawaiian Islands. From the comparison of the calculations based on dropwindsonde and radiosonde data and reports from commercial and military aircraft, it is concluded that the calculations of water vapor flow across latitude lines probably provide a fair representation of reality, especially when based on the dropwindsonde data. However, water vapor flow out of small volumes is not well represented by the results from either data.

Thompson, A. H.↗
NASA NTRS2001

Physical Processes Governing Atmospheric Trace Constituents Measured from an Aircraft on PEM-Tropics

Before the mission, the PI (principal investigator) was instrumental in securing real-time use of the new 51-level ECMWF (European Centre for Medium Range Weather Forecasts) meteorological data. During the mission, he provided flight planning and execution guidance as meteorologist for the P-3B. Mr. Yong Zhu computed and plotted meteorological forecast maps using the ECMWF data and transmitted them to the field from MIT (Massachusetts Institute of Technology). Dr. John Cho was in the field for the Christmas Island portion to extract data from the on-site NOAA (National Oceanic and Atmospheric Administration) radars for local wind profiles that were used at the flight planning meetings. When the power supply for the VHF radar failed, he assisted the NOAA engineer in its repair. After the mission, Mr. Zhu produced meteorological data memos, which were made available to the PEM (Pacific Exploratory Mission)-Tropics B science team on request. An undergraduate student, Ms. Danielle Morse, wrote memos annotating the cloud conditions seen on the aircraft external monitor video tapes. Dr. Cho and the PI circulated a memo regarding the status (and associated problems) of the meteorological measurement systems on the DC-8 and P-3B to the relevant people on the science team. Several papers by members of our project were completed and accepted by JGR (Journal of Geophysical Research) for the first special section on PEM-Tropics B. These papers included coverage of the following topics: 1) examination of boundary layer data; 2) water vapor transport; 3) tropospheric trace constituent layers; 4) summarizations of the meteorological background and events during PEM-Tropics B; 5) concomitant lidar measurements of ozone, water vapor, and aerosol.

Newell, Reginald E.↗
NASA NTRS1988

Observations and wind-forced model simulations of the mean seasonal cycle in tropical Pacific sea surface topography

This paper quantitatively evaluates simulations of the mean seasonal cycle in the tropical Pacific Ocean, using a multiple vertical-mode version of the Busalacchi and O'Brien (1980) linear model. The period studied (1979-1981) includes several coincident oceanic and surface wind data sets, as well as a fairly regular seasonal cycle leading into the 1982-1983 El Nino. Simulated mean seasonal cycles in dynamic height and sea level are compared with observed variations in expendable bathythermograph and island tide gauge data averaged over the same period. It was found that, although all simulations show characteristic features of the mean meridional ridge-trough structure in surface topography, simulated north and south equatorial ridges at 20 deg N and 20 deg S are much higher than those observed. Only weak equatorial ridges were generated near 4 N, and none of the simulations exhibited a significant equatorial trough. These discrepancies are attributed to limitations in model physics and to the wind forcing.

Mcphaden, Michael J.↗
NASA NTRS1995

Sea surface topography fields of the tropical Pacific from data assimilation

Time series of maps of monthly tropical Pacific dynamic topography anomalies from 1979 through 1985 were constructed by means of assimilation of the tide gauge and expendable bathythermograph (XBT) data into a linear model driven by observed winds. Estimates of error statistics were calculated and compared to actual differences between hindcasts and observations. Four experiements were performed as follows: one with no assimilation, one with assimiation of sea level anomaly data from eight selected island tide gauge stations, one with assimilation of dynamic height anomalies derived from XBT data, and one with both XBT and tide gauge data assimilated. Data from seven additional tide gauge stations were withheld from the assimilation process and used for verification in all four experiements. Statistical objective maps based on data alone were also constructed for comparison purposes. The dynamic response of the model without assimilation was, in general, weaker than the observed response. Assimilation resulted in enhanced signal amplitude in all three assimilation experiments. With few exceptions the error estimated generated by the Kalman filter appeared quite reasonable. Since the error processes cannot be assumed to be white or stationary, we could find no straightforward way to test the formal statistical hypothesis that the time series of differences between the filter ouput and the actual observations were drawn from a population with statistics given by the Kalman filter estimaes. We found that the best filter we could devise was still short of the goal of producing a white innovation sequence. Extensive changes in the assumed error statistics make only marginal differences. The same is true for long time and space scale behavior of different models with richer physics and finer resolution. Better data assimilation results will probably require relaxation of the assumptions of stationarity and serial independence of the errors. Formation of such detailed noise models will require longer time series, with the attendant problems of matching very different data sets.

Miller, Robert N.↗
NASA NTRS1996

A Comparison of Aircraft and Ground-Based Measurements at Mauna Loa Observatory, Hawaii, During GTE PEM-West and MLOPEX 2

During October 19-20, 1991, one flight of the NASA Global Tropospheric Experiment (GTE) Pacific Exploratory Mission (PEM-West A) mission was conducted near Hawaii as an intercomparison with ground-based measurements of the Mauna Loa Observatory Photochemistry Experiment (MLOPEX 2) and the NOAA Climate Modeling and Diagnostics Laboratory (CMDL). Ozone, reactive nitrogen species, peroxides, hydrocarbons, and halogenated hydrocarbons were measured by investigators aboard the DC-8 aircraft and at the ground site. Lidar cross sections of ozone revealed a complex air mass structure near the island of Hawaii which was evidenced by large variation in some trace gas mixing ratios. This variation limited the time and spatial scales for direct measurement intercomparisons. Where differences occurred between measurements in the same air masses, the intercomparison suggested that biases for some trace gases was due to different calibration scales or, in some cases, instrumental or sampling biases. Relatively large uncertainties were associated with those trace gases present in the low parts per trillion by volume range. Trace gas correlations were used to expand the scope of the intercomparison to identify consistent trends between the different data sets.

Atlas, E.↗
NASA NTRS2024

Hawai’i Climate: Utilizing NASA Earth Observations to Assess Thermal Stress Impacts on Coastal Hawaiian Fishponds

Hawaiian fishponds (loko i’a), ancient aquaculture systems created over 1500 years ago, historically served to harvest prized native fish species. Colonization-induced changes in land management have reduced active loko i’a from over 500 to ~20, destabilizing nearshore ecosystems and diminishing native Hawaiian cultural traditions. In recent decades, efforts to restore loko i’a have intensified as part of a broader emphasis on preserving Hawaiian cultural identity. Anthropogenic-induced climate change threatens these systems, particularly through the increase in frequency and magnitude of marine heatwaves. Though largely unexplored, these events are effectively studied utilizing remote sensing via Earth observations. Leveraging this technique enables autonomous extraction of water quality parameters to inform fishpond management. This study examined seven loko i’a across the main Hawaiian Islands (Hawai’i Island, Moloka’i, Maui, O’ahu, Kaua’i). Sea surface temperature and normalized difference chlorophyll index measurements were derived in fishponds utilizing Landsat 8 Thermal Infrared Sensor Thermal Infrared Sensor and Sentinel-2 MultiSpectral Instrument between 2013 to 2023, while regional patterns in temperature and chlorophyll-a were observed via Aqua’s Moderate Resolution Imaging Spectroradiometer (2002-2021). Employing these sensors, we focused analysis around the 2015 and 2019 marine heatwaves in the Pacific. We observed a heat stress gradient across the archipelago, creating thermally sheltered and unsheltered fishponds, yet identified no notable localized relationships between temperature and chlorophyll-a. Additionally, we applied pre-determined thermal maxima for culturally significant fish species (Striped Mullet: Mugil cephalus; Milkfish: Chanos Chanos) to assess historical habitat suitability within fishponds. While the direct impacts of marine heatwaves on loko i’a ecology are unknown, temperature patterns observed in this study are cause for concern.

Raz Wachtel↗
NASA NTRS1992

A test of present-day plate geometries for northeast Asia and Japan

Alternative geometries for the present-day configuration of plate boundaries in northeast Asia and Japan are tested using NUVEL-1 and 256 horizontal earthquake slip vectors from the Japan and northern Kuril trenches. Statistical analysis of the slip vectors is used to determine whether the North American, Eurasian, or Okhotsk plate overlies the trench. Along the northern Kuril trench, slip vectors are well-fit by the NUVEL-1 Pacific-North America Euler pole, but are poorly fit by the Pacific-Eurasia Euler pole. Results for the Japan trench are less conclusive, but suggest that much of Honshu and Hokkaido are also part of the North American plate. The simplest geometry consistent with the trench slip vectors is a geometry in which the North American plate extends south to 41 deg N, and possibly includes northern Honshu and southern Hokkaido. Although these results imply that the diffuse seismicity that connects the Lena River delta to Sakhalin Island and the eastern Sea of Japan records motion between Eurasia and North America, onshore geologic and seismic data define an additional belt of seismicity in Siberia that cannot be explained with this geometry. Assuming that these two seismic belts constitute evidence for an Okhotsk block, two published kinematic models for motion of the Okhotsk block are tested. The first model, which predicts motion of up to 15 mm/yr relative to North America, is rejected because Kuril and Japan trench slip vectors are fit more poorly than for the simpler geometry described above. The second model gives a good fit to the trench slip vectors, but only if Okhotsk-North America motion is slower than 5 mm/yr.

Demets, Charles↗
NASA NTRS1996

Measurement of Reactive Nitrogen Compounds over the Tropical Pacific

This report covers the Tropospheric Trace Gas and Airborne Measurement Group's (TTGAMG) participation in the NASA Global Tropospheric Experiment (GTE) Pacific Exploratory Mission: Tropics A (PEM-TA) field measurement program. With other university and NASA centers, the Georgia Institute of Technology Airborne Laser Induced Fluorescence Experiment (GITALIFE) was deployed on the NASA Ames DC-8 aircraft for the measurement of NO and NO2 One of the PEM-TA objectives was to collect the data and interpret the fast photo-chemical processes taking place in the remote and relatively pristine environment over Hawaii, Tahiti, Easter Island, New Zealand, and Fiji.

Sandholm, Scott↗
NASA NTRS2013

ARM Research in the Equatorial Western Pacific: A Decade and Counting

The tropical western Pacific (TWP) is an important climatic region. Strong solar heating, warm sea surface temperatures, and the annual progression of the intertropical convergence zone (ITCZ) across this region generate abundant convective systems, which through their effects on the heat and water budgets have a profound impact on global climate and precipitation. In order to accurately evaluate tropical cloud systems in models, measurements of tropical clouds, the environment in which they reside, and their impact on the radiation and water budgets are needed. Because of the remote location, ground-based datasets of cloud, atmosphere, and radiation properties from the TWP region have come primarily from short-term field experiments. While providing extremely useful information on physical processes, these short-term datasets are limited in statistical and climatological information. To provide longterm measurements of the surface radiation budget in the tropics and the atmospheric properties that affect it, the Atmospheric Radiation Measurement program established a measurement site on Manus Island, Papua New Guinea, in 1996 and on the island republic of Nauru in late 1998. These sites provide unique datasets now available for more than 10 years on Manus and Nauru. This article presents examples of the scientific use of these datasets including characterization of cloud properties, analysis of cloud radiative forcing, model studies of tropical clouds and processes, and validation of satellite algorithms. New instrumentation recently installed at the Manus site will provide expanded opportunities for tropical atmospheric science.

tropical regions↗
NASA NTRS2011

Gravity and Rossby Wave Signatures in the Tropical Troposphere and Lower Stratosphere Based on Southern Hemisphere Additional Ozonesondes (SHADOZ), 1998-2007

Prior investigations attempted to determine the relative influence of advection and convective processes on ozone and water vapor distributions in the tropical tropopause layer (TTL) through analyses of tracers, related physical parameters (e.g., outgoing long-wave radiation, precipitable water, and temperature), or with models. In this study, stable laminae in Southern Hemisphere Additional Ozonesonde Network (SHADOZ) ozone profIles from 1998 to 2007 are interpreted in terms of gravity waves (GW) or Rossby waves (RW) that are identified with vertical and quasi-horizontal displacements, respectively. Using the method of Pierce and Grant (1998) as applied by Thompson et al. (2007a, 2007b, 2010, 2011), amplitudes and frequencies in ozone laminae are compared among representative SHADOZ sites over Africa and the Pacific, Indian, and Atlantic oceans. GW signals maximize in the TTL and lower stratosphere. Depending on site and season, GW are identified in up to 90% of the soundings. GW are most prevalent over the Pacific and eastern Indian oceans, a distribution consistent with vertically propagating equatorial Kelvin waves. Ozone laminae from RW occur more often below the tropical tropopause and with lower frequency 20%). Gravity wave and Rossby wave indices (GWI, RWI) are formulated to facilitate analysis of interannual variability of wave signatures among sites. GWI is positively correlated with a standard ENSO (El Nino-Southern Oscillation) index over American Samoa (14degS, 171degW) and negatively correlated at Watukosek, Java (7.5degS, 114degE), Kuala Lumpur (3degN, 102degE), and Ascension Island (80degS, 15degW). Generally, the responses of GW and RW to ENSO are consistent with prior studies.

Thompson, Anne M.↗
NASA NTRS1976

Strain buildup and release, earthquake prediction and selection of VLB sites for the margins of the North Pacific

Microearthquake studies of the southern section of the San Andreas fault system were conducted in order to elucidate the role of known but little studied complications in the fault system which could affect the SAFE measurement. Data reduction from microearthquake studies in Baja California, Mexico, was completed. In addition, styles of deformation on the Alpine fault in New Zealand and on the San Andreas fault were compared. Sections of these faults with comparable physical characteristics seem to deform in a similar manner, indicating that deformation style is controlled by certain fundamental relations and will continue in the future. The geology of eastern New Guinea is also discussed. Deformation in the area is proposed to be related to collision of a series of island arcs with central New Guinea, which is part of the Australian continent. Among other unusual properties, eastern New Guinea contains the highest anomaly of the gravimetrically determined geoid based on GEM 6 and surface gravity data.

Scholz, C. H.↗
NASA NTRS1996

A New Method of Deriving Time-Averaged Tropospheric Column Ozone over the Tropics Using Total Ozone Mapping Spectrometer (TOMS) Radiances: Intercomparison and Analysis Using TRACE A Data

Error analysis of archived total 03 from total ozone mapping spectrometer (TOMS) (version 6) presented. Daily total 03 maps for the tropics, from the period October 6-21, 1992, are derived from TOMS radiances following correction for these errors. These daily maps, averaged together, show a wavelike feature, which is observed in all latitude bands, underlying sharp peaks which occur at different longitudes depending on the latitude. The wave pattern is used to derive both time-averaged stratospheric and tropospheric 03 fields. The nature of the wave pattern (stratospheric or tropospheric) cannot be determined with certainty due to missing data (no Pacific sondes, no lower stratospheric Stratospheric Aerosol and Gas Experiment (SAGE) ozone for 18 months after the Mt. Pinatubo eruption) and significant uncertainties in the corroborative satellite record in the lower stratosphere (solar backscattered ultraviolet (SBUV), microwave limb sounder (MLS)). However, the time- averaged tropospheric ozone field, based on the assumption that the wave feature is stratospheric, agrees within 10% with ultraviolet differential absorption laser Transport and Atmospheric Chemistry near the Equator-Atlantic) (TRACE A) 03 measurements from the DC-8 and with ozonesonde measurements over Brazzaville, Congo, Ascension Island, and Natal, Brazil, for the period October 6-21, 1992. The derived background (nonpolluted) Indian Ocean tropospheric ozone amount, 26 Dobson units (DU), agrees with the cleanest African ozonesonde profiles for September-October 1992. The assumption of a totally tropospheric wave (flat stratosphere) gives 38 DU above the western Indian Ocean and 15-40% disagreements with the sondes. Tropospheric column 03 is high from South America to Africa, owing to interaction of dynamics with biomass burning emissions. Comparison with fire distributions from advanced very high resolution radiometer (AVHHR) during October 1992 suggests that tropospheric 03 produced from biomass burning in South America and Africa dominates the 03 budget in the tropical southern hemisphere during the study period.

Kim, J. H.↗
NASA NTRS2002

Oceanic Impact: Mechanisms and Environmental Perturbations

The contents include the following: Oceanic impacts-a growing field of fundamental geoscience. Shock metamorphism on the ocean floor (numerical simulations). Numerical modeling of impact-induced modifications of the deep-sea floor. Computer modelling of the water resurge at a marine impact: the Lockne crater, Sweden. Experimental investigation of the role of water in impact vaporization chemistry. Calcareous plankton stratigraphy around the Pliocene Eltanin asteroid impact area (SE Pacific): documentation and application for geological and paleoceanographic reconstruction. Composition of impact melt debris from the Eltanin impact strewn field, Bellingshausen Sea. Iridium concentrations and abundances of meteoritic ejecta from the Eltanin impact in sediment cores from Polarstern expedition ANT XII/4. Unmelted meteoritic debris collected from Eltanin ejecta in Polarstern cores from expedition ANT XII/4. Impact tsunami-Eltanin. Ancient impact structures on modern continental shelves: The Chesapeake Bay, Montagnais, and Toms Canyon craters, Atlantic margin of North America. The Mjolnir marine impact crater porosity anomaly. Kardla (Hiiu-maa Island, Estonia) - the buried and well-preserved Ordovician marine impact structure. Long-term effect of the Kardla crater (Hiiu-maa, Estonia) on Late Ordovician carbonate sedimentation. The middle Devonian Kaluga impact crater (Russia): new interpretation of marine setting.

Gersonde, Rainer↗
NASA NTRS2004

Spectral Absorption of Solar Radiation by Aerosols during ACE-Asia

As part of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia), the upward and downward spectral solar radiant fluxes were measured with the Spectral Solar Flux Radiometer (SSFR), and the aerosol optical depth was measured with the Ames Airborne Tracking Sunphotometer (AATS-14) aboard the Center for INterdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft. IN this paper, we examine the data obtained for two cases: a moderately thick aerosol layer, 12 April, and a relatively thin aerosol case, 16 April 2001. ON both days, the Twin Otter flew vertical profiles in the Korean Strait southeast of Gosan Island. For both days we determine the aerosol spectral absorption of the layer and estimate the spectral aerosol absorption optical depth and single-scattering albedo. The results for 12 April show that the single-scattering albedo increases with wavelength from 0.8 at 400 nm to 0.95 at 900 nm and remains essentially constant from 950 to 1700 nm. On 16 April the amount of aerosol absorption was very low; however, the aerosol single-scattering albedo appears to decrease slightly with wavelength in the visible region. We interpret these results in light of the two absorbing aerosol species observed during the ACE-asia study: mineral dust and black carbon. The results for 12 April are indicative of a mineral dust-black carbon mixture. The 16 April results are possibly caused by black carbon mixed with nonabsorbing pollution aerosols. For the 12 April case we attempt to estimate the relative contributions of the black carbon particles and the mineral dust particles. We compare our results with other estimates of the aerosol properties from a Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) satellite analysis and aerosol measurements made aboard the Twin Otter, aboard the National Oceanic and Atmospheric Administration Ronald H Brown ship, and at ground sites in Gosan and Japan. The results indicate a relatively complicated aerosol mixture of both industrial pollution (including black carbon) and mineral dust. This underscores the need for careful measurements and analysis to separate out the absorption effects of mineral dust and black carbon in the east Asia region.

Bergstrom, R. W.↗
NASA NTRS2002

Insights into Tropical Tropospheric Ozone from the 1998-2000 SHADOZ (Southern Hemisphere Additional Ozonesondes) Data Record

We describe the first overview of total, stratospheric and tropospheric ozone in the southern hemisphere tropics based on a three year, ten site record of ozone soundings from the Southern Hemisphere Additional Ozonesondes (SHADOZ) network. Observations covering 1998-2000 were made over Ascension Island; Nairobi, Kenya; Irene, South Africa; Reunion Island; Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; Natal, Brazil. The ozone data, with simultaneous temperature profiles to approximately 7 hPa and relative humidity to approximately 200 hPa, are at an archive: http://code9l6. gsfc.nasa.gov/Data_services/shadoz. Prominent features are highly variable tropospheric ozone, a zonal wave-one pattern in total (and tropospheric) column ozone, and signatures of the Quasi-Biennial Oscillation (QBO) in stratospheric ozone. Total, stratospheric and tropospheric column ozone amounts usually peak between August and November and are lowest in the first half of the year. Tropospheric ozone variability over the Indian and Pacific Ocean displays influences of the waning 1997-1998 Indian Ocean Dipole and ENSO (El Nino / Southern Oscillation), seasonal convection and pollution transport from Africa. Tropospheric ozone over the Atlantic Basin reflects regional subsidence and recirculation as well as pollution ozone from biomass burning.

Thompson, Anne M.↗
NASA NTRS2004

SHADOZ (Southern Hemisphere Additional Ozonesondes): A Project Overview and New Insights on Tropical Tropospheric Ozone

The SHADOZ (Southern Hemisphere Additional Ozonesondes) ozone sounding network was initiated in 1998 to improve the coverage of tropical in-situ ozone measurements for satellite validation, algorithm development and related process studies. Over 2000 soundings have been archived at the website, http://croc.gsfc.nasa.gov/shadoz, for 12 stations: Ascension Island; Nairobi and Malindi, Kenya; Irene, South Africa; Reunion Island; Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; Natal, Brazil; Paramaribo, Surinam. Key results from SHADOZ will be described from among the following: 1) By using ECC sondes with similar procedures, 5-10% accuracy and precision (1-sigma) of the sonde total ozone measurement is achieved; 2) Week-to-week variability in tropospheric ozone is so great that statistics are frequently not Gaussian; most stations vary up to a factor of 3 in tropospheric column over the course of a year; 3) Longitudinal variability in tropospheric ozone profiles is a consistent feature, with a 10-15 DU column-integrated difference between Atlantic and Pacific sites; this causes a "zonal wave-one" feature in total ozone; 4) The ozone record from Paramaribo, Surinam (6N, 55W) is a marked contrast to southern tropical ozone because Surinam is often north of the Intertropical Convergence Zone.

Thompson, Anne M.↗
NASA NTRS2004

New Insights on Tropical Ozone from SHADOZ (Southern Hemisphere Additional Ozonesondes) Profiles

The SHADOZ (Southern Hemisphere Additional Ozonesondes) ozone sounding network was initiated in 1998 to improve the coverage of tropical in-situ ozone measurements for satellite validation, algorithm development and related process studies. Over 2000 soundings have been archived at the website, , for 12 stations: Ascension Island; Nairobi and Malindi, Kenya; Irene, South Africa; Reunion Island, Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; Natal, Brazil; Paramaribo, Surinam. Key results from SHADOZ will be described from among the following: 1) By using ECC sondes with similar procedures, 5-10% accuracy and precision (1-sigma) of the sonde total ozone measurement was achieved; 2) Week-to-week variability in tropospheric ozone is so great that statistics are frequently not Gaussian; most stations vary up to a factor of 3 in tropospheric column over the course of a year; 3) Longitudinal variability in tropospheric ozone profiles is a consistent feature, with a 10-15 DU column-integrated difference between Atlantic and Pacific sites; this causes a "zonal wave-one" feature in total ozone. 4) The ozone record from Paramaribo, Surinam (6N, 55W) is a marked contrast to southern tropical ozone because Surinam is often north of the Intertropical Convergence Zone; 5) Indian Ocean region pollution may contribute up to half of the excess ozone observed in the south tropical Atlantic paradox in the December-January-February period of the year.

Thompson, Anne M.↗