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NASA NTRS2007

The 'Weekend Effect' in Tropospheric NO2 Seen from the Ozone Monitoring Instrument

The Ozone Monitoring Instrument has gathered daily global data on NO2 and other atmospheric trace gases since its launch on the EOS Aura satellite in 2004. The large accumulated data set makes it possible to monitor changes of both meteorological and anthropogenic origin in tropospheric NOz amounts. In particular, averages on time scales on the order of a year show a distinct 'weekend effect' in NO2 variation, with smaller NO2 amounts seen on Saturday and/or Sunday than on the remaining weekdays. Using the OMI NO2 Standard Product (SP), we examine this effect in relation to geopolitical boundaries and investigate implications for identifying sources. We also use the SP data to find evidence for other short-term anthropogenic changes in NO2 emissions over heavily polluted regions including the United States, Europe and China.

Bucsela, E.↗
NASA NTRS2008

Maneuver Planning for Conjunction Risk Mitigation with Ground-track Control Requirements

The planning of conjunction Risk Mitigation Maneuvers (RMM) in the presence of ground-track control requirements is analyzed. Past RMM planning efforts on the Aqua, Aura, and Terra spacecraft have demonstrated that only small maneuvers are available when ground-track control requirements are maintained. Assuming small maneuvers, analytical expressions for the effect of a given maneuver on conjunction geometry are derived. The analytical expressions are used to generate a large trade space for initial RMM design. This trade space represents a significant improvement in initial maneuver planning over existing methods that employ high fidelity maneuver models and propagation.

McKinley, David↗
NASA NTRS2008

NASA's Earth Observations of the Global Environment: Our Changing Planet and the View from Space

Observations of the Earth from space over the past 30 years has enabled an increasingly detailed view of our Earth's atmosphere, land, oceans, and cryosphere, and its many alterations over time. With the advent of improvements in technology, together with increased understanding of the physical principles of remote sensing, it is now possible to routinely observe the global distribution of atmospheric constituents, including both cloud and aerosol optical properties, land surface reflectance, sea ice and glaciers, and numerous properties of the world's oceans. This talk will review the current status of recent NASA Earth observing missions, and summarize key findings. These missions include EOS missions such as Landsat 7, QuikScat, Terra, Jason-1, Aqua, ICESat, SORCE, and Aura, as well as Earth probe missions such as TRMM and SeaWiFS. Recent findings from Cloud- Sat and CALIPSO from the Earth System Science Pathfinder program will also be summarized, if time permits. Due to its wide utilization by the Earth science community, both in the US and abroad, special emphasis will be placed on the Moderate Resolution Imaging Spectroradiometer (MODIS), developed by NASA and launched onboard the Terra spacecraft in 1999 and the Aqua spacecraft in 2002. As the quintessential instrument of the Earth Observing System, it is widely used for studies of the oceans, land, and atmosphere, and its lengthening time series of Earth observations is finding utilization in many communities for both climate, weather, and applications use.

King, Michael D.↗
NASA NTRS2008

The GEOS Chemistry Climate Model: Comparisons to Satellite Data

The Goddard Earth Observing System Chemistry Climate Model (GEOS CCM) has been developed by combining the atmospheric chemistry and transport modules developed over the years at Goddard and the GEOS general circulation model, also developed at Goddard. We will compare model simulations of ozone, and the minor constituents that affect ozone, for the period around 1980 with newly released revised data from the Limb Infrared Monitor of the Stratosphere (LIMS) instrument on Nimbus 4. We will also compare model simulations for the period of the early 2000s with the data from the Microwave Limb Sounder (MLS) and the High Resolution Dynamic Limb Sounder (HRDLS) on the Aura satellite. We will use these comparisons to examine the performance of the model for the present atmosphere and for the change that has occurred during the last 2 decades of ozone loss due to chlorine and bromine compounds released from chlorofluorocarbons and halons.

Stolarski, Richard S.↗
NASA NTRS2008

Effects of the 2006 El Nino on Tropospheric Ozone and Carbon Monoxide: Implications for Dynamics and Biomass Burning

We have studied the effects of the 2006 El Nino on tropospheric O3 and CO at tropical and sub-tropical latitudes measured from the OMI and MLS instruments on the Aura satellite. The 2006 El Nino-induced drought allowed forest fires set to clear land to burn out of control during October and November in the Indonesian region. The effects of these fires are clearly seen in the enhancement of GO concentration measured from the MLS instrument. We have used a global model of atmospheric chemistry and transport (GMI CTM) to quantify the relative irrrportance of biomass burning and large scale transport: in producing observed changes in tropospheric O3 and CO . The model results show that during October and November both biomass burning and meteorological changes contributed almost equally to the observed increase in tropospheric O3 in the Indonesian region. The biomass component was 4-6 DU but it was limited to the Indonesian region where the fires were most intense, The dynamical component was 4-8 DU but it covered a much larger area in the Indian Ocean extending from South East Asia in the north to western Australia in the south. By December 2006, the effect of biomass taming was reduced to zero and the obsemed changes in tropospheric O3 were mostly due to dynamical effects. The model results show an increase of 2-3% in the global burden of tropospheric ozone. In comparison, the global burdean of CO increased by 8-12%.

Chandra, S.↗
NASA NTRS2008

Evolution of the Earth Observing System (EOS) Data and Information System (EOSDIS)

One of the strategic goals of the U.S. National Aeronautics and Space Administration (NASA) is to "Develop a balanced overall program of science, exploration, and aeronautics consistent with the redirection of the human spaceflight program to focus on exploration". An important sub-goal of this goal is to "Study Earth from space to advance scientific understanding and meet societal needs." NASA meets this subgoal in partnership with other U.S. agencies and international organizations through its Earth science program. A major component of NASA s Earth science program is the Earth Observing System (EOS). The EOS program was started in 1990 with the primary purpose of modeling global climate change. This program consists of a set of space-borne instruments, science teams, and a data system. The instruments are designed to obtain highly accurate, frequent and global measurements of geophysical properties of land, oceans and atmosphere. The science teams are responsible for designing the instruments as well as scientific algorithms to derive information from the instrument measurements. The data system, called the EOS Data and Information System (EOSDIS), produces data products using those algorithms as well as archives and distributes such products. The first of the EOS instruments were launched in November 1997 on the Japanese satellite called the Tropical Rainfall Measuring Mission (TRMM) and the last, on the U.S. satellite Aura, were launched in July 2004. The instrument science teams have been active since the inception of the program in 1990 and have participation from Brazil, Canada, France, Japan, Netherlands, United Kingdom and U.S. The development of EOSDIS was initiated in 1990, and this data system has been serving the user community since 1994. The purpose of this chapter is to discuss the history and evolution of EOSDIS since its beginnings to the present and indicate how it continues to evolve into the future. this chapter is organized as follows. Sect. 7.2 provides a discussion of EOSDIS, its elements and their functions. Sect. 7.3 provides details regarding the move towards more distributed systems for supporting both the core and community needs to be served by NASA Earth science data systems. Sect. 7.4 discusses the use of standards and interfaces and their importance in EOSDIS. Sect. 7.5 provides details about the EOSDIS Evolution Study. Sect. 7.6 presents the implementation of the EOSDIS Evolution plan. Sect. 7.7 briefly outlines the progress that the implementation has made towards the 2015 Vision, followed by a summary in Sect. 7.8.

Ramapriyan, Hampapuram K.↗
NASA NTRS2008

Accurate Satellite-Derived Estimates of Tropospheric Ozone Radiative Forcing

Estimates of the radiative forcing due to anthropogenically-produced tropospheric O3 are derived primarily from models. Here, we use tropospheric ozone and cloud data from several instruments in the A-train constellation of satellites as well as information from the GEOS-5 Data Assimilation System to accurately estimate the instantaneous radiative forcing from tropospheric O3 for January and July 2005. We improve upon previous estimates of tropospheric ozone mixing ratios from a residual approach using the NASA Earth Observing System (EOS) Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) by incorporating cloud pressure information from OMI. Since we cannot distinguish between natural and anthropogenic sources with the satellite data, our estimates reflect the total forcing due to tropospheric O3. We focus specifically on the magnitude and spatial structure of the cloud effect on both the shortand long-wave radiative forcing. The estimates presented here can be used to validate present day O3 radiative forcing produced by models.

Joiner, Joanna↗
NASA NTRS2009

Small Earth Observing Satellites Flying with Large Satellites in the A-Train

This paper/poster presents a real-life example of the benefits of flying small satellites with other satellites, large or small, and vice versa. Typically, most small satellites fly payloads consisting of one or two instruments and fly in orbits that are independent from that of other satellites. The science data from these satellites are either used in isolation or correlated with instrument data from other satellites. Data correlation with other satellites is greatly improved when the measurements of the same point or air mass are taken at approximately the same time. Scientists worldwide are beginning to take advantage of the opportunities for improved data correlation, or coincidental science, offered by the international Earth Observing Constellation known as the A-Train (sometimes referred to as the Afternoon Constellation). Most of the A-Train satellites are small - the A-Train is anchored by two large NASA satellites (EOS-Aqua and EOS-Aura), but consists also of 5 small satellites (CloudSat, CALIPSO, PARASOL, OCO and Glory these last two will join in 2009). By flying in a constellation, each mission benefits from coincidental observations from instruments on the other satellites in the constellation. Essentially, from a data point of view, the A-Train can be envisioned as a single, virtual science platform with multiple instruments. Satellites in the A-Train fly at 705 km in sun-synchronous orbits. Their mean local times at the equator are within seconds to a few minutes of each other. This paper describes the challenges of operating an international constellation of independent satellites from the U.S. and Europe to maximize the coincidental science opportunities while at the same time minimizing the level of operational interactions required between team members. The A-Train mission teams have been able to demonstrate that flying as members of an international constellation does not take away the flexibility to accommodate new requirements. Specific examples will be cited, including CloudSat's relocation (to accommodate a new viewing angle for the CALIPSO satellite), Glory's replan to move closer to PARASOL, and OCO's long term plans to minimize on-orbit operations costs while maintaining safety. In all cases, safety is ensured, science returns are enhanced, and operational flexibility is retained to the maximum extent possible.

Kelly, Angelita C.↗
NASA NTRS2006

New Raman Water Vapor and Temperature Lidar at JPL Table Mountain Facility: Optimization, Validations and Sonde Intercomparison

Jet Propulsion Laboratory currently operates lidar systems at Table Mountain Facility (TMF), California (34.4 deg N, 117.7 deg W at 2300m) and Mauna Loa Observatory (MLO), Hawaii (19.5 deg N, 155.6 deg W at 3400m) under the Network for the Detection of Atmospheric Composition Change (NDACC, formerly NDSC). To complement existing NDACC lidars at TMF, which acts as a primary site for inter-comparisons, a new water vapor and temperature lidar has begun routine operation with typically 3-4 nightly profiles per week. As water vapor is a key greenhouse gas, and is highly variable on annual and seasonal cycles, accurate long term measurements are necessary for predictions of climate change and to increase our understanding of the atmospheric processes it contributes to. The new TMF lidar has demonstrated high spatial and temporal resolution, with a high degree of optimization being achieved over the past year, although the authors believe further improvement may yet be possible. The lidar has been designed for accuracies of 5% up to 12km in the free troposphere with the capability to measure to the tropopause and lower stratosphere with accuracies of 1 ppm. It is anticipated that the data sets produced will be used for Aura validation and for incorporation into NDACC archives. Validation results for the optimized system are presented with intercomparisons using Vaisala RS92-K radiosondes.

water vapor↗
NASA NTRS2009

Lightning-Generated NO(x) Seen By OMI during NASA's TC-4 Experiment: First Results

We present here case studies identifying upper-tropospheric NO2 produced in convective storms during NASA's Tropical Composition, Cloud and Climate Coupling Experiment (TC~i)n July and August 2007. DC8 aircraft missions, flown from the mission base in Costa Rica, recorded in situ NO2 profiles near active storms and in relatively quiet areas. We combine these data with measurements from the Ozone Monitoring Instrument (OMI) on the Aura satellite to estimate the amount of NO2 produced by lightning (LN02) above background levels in the regions influenced by storms. In our analysis, improved off-line processing techniques are employed to minimize known artifacts in the OM1 data. Information on lightning flashes (primarily CG) observed by the surface network operated by the Instituto Costarricense de Electricidad are examined upwind of regions where OM1 indicates enhanced LNO2. Comparisons of the observed flash data with measurements by the TRMM/LIS satellite instrument are used to obtain the lightning detection efficiency for total flashes. Finally, using the NO/NO2 ratio estimated from DC-8 observations, we estimate the average NO(x) production per lightning flash for each case in this study. The magnitudes of the measured NO(x) enhancements are compared with those observed by the DC-8 and with similar OM1 measurements analyzed in mid-latitude experiments.

Bucsela, Eric↗
NASA NTRS2008

Intercomparison of SCIAMACHY and OMI Tropospheric NO2 Columns: Observing the Diurnal Evolution of Chemistry and Emissions from Space

Concurrent (August 2006) measurements of tropospheric NO2 columns from OMI aboard Aura (1330 local overpass time) and SCIAMACHY aboard Envisat (1000 local overpass time) offer an opportunity to examine the consistency between the two instruments under tropospheric background conditions and the effect of different observing times. For scenes with tropospheric NO 2 columns <5.0 x 10(exp 15) molecules cm 2, SCIAMACHY and OMI agree within 1.0-2.0 x 10(exp 15) molecules cm 2, consistent with the detection limits of both instruments. We find evidence for a low bias of 0.2 x 10(exp 15) molecules cm 2 in OMI observations over remote oceans. Over the fossil fuel source regions at northern midlatitudes, we find that SCIAMACHY observes up to 40% higher NO2 at 1000 local time (LT) than OMI at 1330 LT. Over biomass burning regions in the tropics, SCIAMACHY observes up to 40% lower NO 2 columns than OMI. These differences are present in the spectral fitting of the data (slant column) and are augmented in the fossil fuel regions and dampened in the tropical biomass burning regions by the expected increase in air mass factor as the mixing depth rises from 1000 to 1330 LT. Using a global 3-D chemical transport model (GEOS-Chem), we show that the 1000-1330 LT decrease in tropospheric NO2 column over fossil fuel source regions can be explained by photochemical loss, dampened by the diurnal cycle of anthropogenic emissions that has a broad daytime maximum. The observed 1000-1330 LT NO2 column increase over tropical biomass burning regions points to a sharp midday peak in emissions and is consistent with a diurnal cycle of emissions derived from geostationary satellite fire counts.

Boersma, K. Folkert↗
NASA NTRS2007

Regulation of H2O and CO in Tropical Tropopause Layer by the Madden-Julian Oscillation

Impacts of the Madden-Julian oscillation (MJO) on the water vapor (H2O) and carbon monoxide (CO) abundances in the tropical tropopause layer (TTL) are investigated using Aura Microwave Limb Sounder (MLS) data for November 2004 to May 2005. The effects of the eastward propagation of MJO on H2O and CO abundances in the TTL are evident. Deep convection transports H20 into the upper troposphere up to about the 355-365 K level. Around the 365-375 K level, a dry anomaly is collocated with a cold anomaly, which is above a warm anomaly located near the region of convection enhancement. Tropical mean H20 at 375 K is regulated by the MJO through convection enhancement and coherent with the local MJO-related temperature variation. The locations of dehydration follow the eastward propagation of convection enhancement and its area extent depends on the phase of the MJO. Enhancement of deep convection associated with the MJO also injects CO from the lower troposphere to the TTL up to 375 K. However, tropical mean CO at 375 K responds instantaneously to the large injection event occurring over the African continent.

Wong, Sun↗
NASA NTRS2007

Effects of Convective Ice Lofting on H2O and HDO in the Tropical Tropopause Layer

We have added convective ice lofting to a Lagrangian trajectory model of near-tropopause water vapor (H2O) and its isotopologue HDO. The ice lofting simulation is based on a parameterization derived from Aura Microwave Limb Sounder (MLS) icewater content measurements. In previous papers, the Lagrangian model has accurately interannual and seasonal H2O abundances; there was no need for convection to be included in the model. We show here that this model does a poor job of simulating near-tropopause HDO, but that the addition of convective ice lofting greatly improves the HDO simulation. Convective ice lofting has a small effect on lower stratospheric H2O. H2O there is set by the minimum temperature encountered at the cold-point tropopause, so H2O added by convection below this level does not make it through this cold point and into the lower stratosphere. Thus, adding convection to the model does not degrade the model's previously demonstrated accurate simulations of H2O. We conclude that the HDO data suggest an important role for convective mass flux into the so-called tropical tropopause layer.

Dessler, A. E.↗
NASA NTRS2009

The Sensitivity of U.S. Surface Ozone Formation to NOx, and VOCs as Viewed from Space

We investigated variations in the sensitivity of surface ozone formation in summer to precursor species concentrations of volatile organic compounds (VOCs) and nitrogen oxides (NO(x)) as inferred from the ratio of tropospheric columns of formaldehyde and nitrogen dioxide from the Aura Ozone Monitoring Instrument (OMI). The data indicate that ozone formation became: 1. more sensitive to NO(x) over most of the U.S, from 2005 to 2007 because of substantial decreases in NO(x) emissions primarily from stationary sources, and 2. more sensitive to NO(x) with increasing temperature, in part because emissions of highly reactive, biogenic isoprene increase with temperature, thus increasing the total VOC reactivity. Based on our interpretation of the data, current strategies implemented to reduce unhealthy levels of surface ozone should focus more on reducing NO(x) emissions, except in some downtown areas which have historically benefited from reductions in VOC emissions.

Duncan, Bryan N.↗
NASA NTRS2008

An Overview of the NASA Spring/Summer 2008 Arctic Campaign - ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites)

ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) is a major NASA led airborne field campaign being performed in the spring and summer of 2008 at high latitudes (http://cloud1.arc.nasa.gov/arctas/). ARCTAS is a part of the International Polar Year program and its activities are closely coordinated with multiple U. S. (NOAA, DOE), Canadian, and European partners. Observational data from an ensemble of aircraft, surface, and satellite sensors are closely integrated with models of atmospheric chemistry and transport in this experiment. Principal NASA airborne platforms include a DC-8 for detailed atmospheric composition studies, a P-3 that focuses on aerosols and radiation, and a B-200 that is dedicated to remote sensing of aerosols. Satellite validation is a central activity in all these platforms and is mainly focused on CALIPSO, Aura, and Aqua satellites. Major ARCTAS themes are: (1) Long-range transport of pollution to the Arctic including arctic haze, tropospheric ozone, and persistent pollutants such as mercury; (2) Boreal forest fires and their implications for atmospheric composition and climate; (3) Aerosol radiative forcing from arctic haze, boreal fires, surface-deposited black carbon, and other perturbations; and (4) Chemical processes with focus on ozone, aerosols, mercury, and halogens. The spring deployment (April) is presently underway and is targeting plumes of anthropogenic and biomass burning pollution and dust from Asia and North America, arctic haze, stratosphere-troposphere exchange, and ozone photochemistry involving HOx and halogen radicals. The summer deployment (July) will target boreal forest fires and summertime photochemistry. The ARCTAS mission is providing a critical link to enhance the value of NASA satellite observations for Earth science. In this talk we will discuss the implementation of this campaign and some preliminary results.

Jacob, Daniel J.↗
NASA NTRS2009

An Intelligent Archive Testbed Incorporating Data Mining

Many significant advances have occurred during the last two decades in remote sensing instrumentation, computation, storage, and communication technology. A series of Earth observing satellites have been launched by U.S. and international agencies and have been operating and collecting global data on a regular basis. These advances have created a data rich environment for scientific research and applications. NASA s Earth Observing System (EOS) Data and Information System (EOSDIS) has been operational since August 1994 with support for pre-EOS data. Currently, EOSDIS supports all the EOS missions including Terra (1999), Aqua (2002), ICESat (2002) and Aura (2004). EOSDIS has been effectively capturing, processing and archiving several terabytes of standard data products each day. It has also been distributing these data products at a rate of several terabytes per day to a diverse and globally distributed user community (Ramapriyan et al. 2009). There are other NASA-sponsored data system activities including measurement-based systems such as the Ocean Data Processing System and the Precipitation Processing system, and several projects under the Research, Education and Applications Solutions Network (REASoN), Making Earth Science Data Records for Use in Research Environments (MEaSUREs), and the Advancing Collaborative Connections for Earth-Sun System Science (ACCESS) programs. Together, these activities provide a rich set of resources constituting a value chain for users to obtain data at various levels ranging from raw radiances to interdisciplinary model outputs. The result has been a significant leap in our understanding of the Earth systems that all humans depend on for their enjoyment, livelihood, and survival. The trend in the community today is towards many distributed sets of providers of data and services. Despite this, visions for the future include users being able to locate, fuse and utilize data with location transparency and high degree of interoperability, and being able to convert data to information and usable knowledge in an efficient, convenient manner, aided significantly by automation (Ramapriyan et al. 2004; NASA 2005). We can look upon the distributed provider environment with capabilities to convert data to information and to knowledge as an Intelligent Archive in the Context of a Knowledge Building system (IA-KBS). Some of the key capabilities of an IA-KBS are: Virtual Product Generation, Significant Event Detection, Automated Data Quality Assessment, Large-Scale Data Mining, Dynamic Feedback Loop, and Data Discovery and Efficient Requesting (Ramapriyan et al. 2004).

Ramapriyan, H.↗
NASA NTRS2009

Recent Biomass Burning in the Tropics and Related Changes in Tropospheric Ozone

Biomass burning is an important source of chemical precursors of tropospheric ozone. In the tropics, biomass burning produces ozone enhancements over broad regions of Indonesia, Africa, and South America including Brazil. Fires are intentionally set in these regions during the dry season each year to clear cropland and to clear land for human/industrial expansion. In Indonesia enhanced burning occurs during dry El Nino conditions such as in 1997 and 2006. These burning activities cause enhancement in atmospheric particulates and trace gases which are harmful to human health. Measurements from the Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) from October 2004-November 2008 are used to evaluate the effects of biomass burning on tropical tropospheric ozone. These measurements show sizeable decreases approx.15-20% in ozone in Brazil during 2008 compared to 2007 which we attribute to the reduction in biomass burning. Three broad biomass burning regions in the tropics (South America including Brazil, western Africa, and Indonesia) were analyzed in the context of OMI/MLS measurements and the Global Modeling Initiative (GMI) chemical transport model developed at Goddard Space Flight Center. The results indicate that the impact of biomass burning on ozone is significant within and near the burning regions with increases of approx.10-25% in tropospheric column ozone relative to average background concentrations. The model suggests that about half of the increases in ozone from these burning events come from altitudes below 3 km. Globally the model indicates increases of approx.4-5% in ozone, approx.7-9% in NO, (NO+NO2), and approx.30-40% in CO.

Ziemke↗
NASA NTRS2008

Validation of SO2 Retrievals from the Ozone Monitoring Instrument over NE China

The Dutch-Finnish Ozone Monitoring Instrument (OMI) launched on the NASA Aura satellite in July 2004 offers unprecedented spatial resolution, coupled with contiguous daily global coverage, for space-based UV measurements of sulfur dioxide (SO2). We present a first validation of the OMI SO2 data with in situ aircraft measurements in NE China in April 2005. The study demonstrates that OMI can distinguish between background SO2 conditions and heavy pollution on a daily basis. The noise (expressed as the standard deviation,sigma) is approximately 1.5 DU (Dobson units; 1 DU = 2.69 10 (exp 16) molecules/cm (exp 2)) for instantaneous field of view boundary layer (PBL) SO2 data. Temporal and spatial averaging can reduce the noise to sigma approximetly 0.3 DU over a remote region of the South Pacific; the long-term average over this remote location was within 0.1 DU of zero. Under polluted conditions collection 2 OMI data are higher than aircraft measurements by a factor of two. Improved calibrations of the radiance and irradiance data (collection 3) result in better agreement with aircraft measurements on polluted days. The air mass corrected collection 3 data still show positive bias and sensitivity to UV absorbing aerosols. The difference between the in situ data and the OMI SO2 measurements within 30 km of the aircraft profiles was about 1 DU, equivalent to approximately 5 ppb from 0 to 3000 m altitude. Quantifying the SO2 and aerosol profiles and spectral dependence of aerosol absorption between 310 and 330 nm are critical for an accurate estimate of SO2 from satellite UV measurements.

Krotkov, Nickolay A.↗