Mission and sampling analyses for atmospheric satellite experiments

Orbital analyses, instrument-viewing geometry studies, and sampling simulations are performed to define mission concepts for advanced atmospheric research satellite experiments. These analyses are conducted in collaboration with NASA Headquarters and working groups consisting of atmospheric scientists and experiment developers. Analytical techniques are developed and used to optimize geographical coverage, sensor-viewing geometries, data gathering strategies, sampling schemes, orbital characteristics, satellite launch times, and operational modes of the various experiments and mission concepts. Short-term (7 day) Shuttle Missions, the Upper Atmosphere Research Satellite (UARS), and multisatellite missions such as the Earth Observing System (EOS) are being studied. Atmospheric experiments which are being analyzed include nadir-viewing sounders, limb-emission scanners, laser systems, and solar-occultation techniques

Extended time observations of California marine stratocumulus clouds from GOES for July 1983-1987

One of the goals of the First ISCCP Regional Experiment (FIRE) is to relate the relatively small scale (spatial and temporal) Intensive Field Observations (IFO) to larger time and space domains embodied in the Extended Time Observations (ETO) phase of the experiment. The data analyzed as part of the ETO are to be used to determine some climatological features of the limited area which encompasses the Marine Stratocumulus IFO which took place between 29 June and 19 July 1987 off the coast of southern California

Cloud parameters derived from GOES during the 1987 marine stratocumulus FIRE Intensive Field Observation (IFO) period

The Geostationary Operational Environmental Satellite (GOES) is well suited for observations of the variations of clouds over many temporal and spatial scales. For this reason, GOES data taken during the Marine Stratocumulus Intensive Field Observations (IFO) (June 29 to July 19, 1987, Kloessel et al.) serve several purposes. One facet of the First ISCCP Regional Experiment (FIRE) is improvement of the understanding of cloud parameter retrievals from satellite-observed radiances. This involves comparisons of coincident satellite cloud parameters and high resolution data taken by various instruments on other platforms during the IFO periods. Another aspect of FIRE is the improvement of both large- and small-scale models of stratocumulus used in general circulation models (GCMs). This may involve, among other studies, linking the small-scale processes observed during the IFO to the variations in large-scale cloud fields observed with the satellites during the IFO and Extended Time Observation (ETO) periods. Preliminary results are presented of an analysis of GOES data covering most of the IFO period. The large scale cloud-field characteristics are derived, then related to a longer period of measurements. Finally, some point measurements taken from the surface are compared to regional scale cloud parameters derived from satellite radiances

Satellite-derived cloud and radiation fields over the marine stratocumulus IFO

The Geostationary Operational Environmental Satellite (GOES) is the only source for nearly continuous areal coverage of clouds within the California marine stratocumulus region. The cloud parameters derived from GOES data during the First ISCCP Regional Experiment (FIRE) Marine Stratocumulus Intensive Field Observations (IFO) are summarized

Cloud parameters from GOES visible and infrared radiances during the FIRE Cirrus IFO, October 1986

Visible (VIS, 0.65 micron) and infrared (IR, 10.5 microns) channels on geostationary satellites are the key elements of the International Satellite Cloud Climatology Project (ISCCP). All daytime ISCCP cloud parameters are derived from a combination of VIS and IR data. Validation and improvement of the ISCCP and other cloud retrieval algorithms are important components of the First ISCCP Regional Experiment (FIRE) Intensive Field Observations (IFO). Data from the Cirrus IFO (October 19 to November 2, 1986) over Wisconsin are available for validating cirrus cloud retrievals from satellites. The Geostationary Operational Environmental Satellite (GOES) located over the Equator at approximately 100 deg W provided nearly continuous measurements of VIS and IR radiances over the IFO areas. The preliminary results of cloud parameters derived from the IFO GOES data are presented. Cloud attitudes are first derived using an algorithms without corrections for cloud emissivity. These same parameters will then be computed from the same data relying on an emissivity correction algorithm based on correlative data taken during the Cirrus IFO

Satellite-derived cloud fields during the FIRE cirrus IFO case study

The First ISCCP Regional Experiment (FIRE) Cirrus Intensive Field Observation (IFO) program measured cirrus cloud properties with a variety of instruments from the surface, aircraft, and satellites. Surface and aircraft observations provide a small scale point and line measurements of different micro- and macro-physical properties of advecting and evolving cloud systems. Satellite radiance data may be used to measure the areal variations of the bulk cloud characteristics over meso- and large scales. Ideally, the detailed cloud properties derived from the small scale measurements should be tied to the bulk cloud properties typically derived from the satellite data. Full linkage of these data sets for a comprehensive description of a given cloud field, one of the goals of FIRE, should lead to significant progress in understanding, measuring, and modeling cirrus cloud systems. The relationships derived from intercomparisons of lidar and satellite data by Minnis et al. are exploited in a mesoscale analysis of the satellite data taken over Wisconsin during the Cirrus IFO case study

A comparison of ISCCP and FIRE satellite cloud parameters

One of the goals of the First ISCCP Regional Experiment (FIRE) is the quantification of the uncertainties in the cloud parameter products derived by the International Satellite Cloud Climatology Project (ISCCP). This validation effort has many facets including sensitivity analyses and comparisons to similar data or theoretical results with known accuracies. The FIRE provides cloud-truth data at particular points or along particular lines from surface and aircraft measurement systems. Relating these data to the larger, area-averaged ISCCP results requires intermediate steps using higher resolution satellite data analyses. Errors in the cloud products derived with a particular method can be determined by performing analyses of high resolution satellite data over the area surrounding the point or line measurement. This same analysis technique may then be used to derive cloud parameters over a larger area containing similar cloud fields. It is assumed that the uncertainties found for the small scale analyses are the same for the large scale so that the method has been calibrated for the particular cloud type; i.e., its accuracy is known. Differences between the large scale results using the ISCCP technique and the calibrated method can be computed and used to determine if any significant biases or rms errors occur in the ISCCP results. Selected ISCCP results are compared to cloud parameters derived using the hybrid bispectral threshold method over the FIRE IFO and extended observation areas

Science requirements for a global change technology architecture trade study

Science requirements for a global change technology initiative (GCTI) Architecture Trade Study were established by reviewing and synthesizing results from recent studies. A scientific rationale was adopted and used to identify a comprehensive set of measureables and their priorities. Spatial and temporal requirements for a number of measurement parameters were evaluated based on results from several working group studies. Science requirements were defined using these study results in conjunction with the guidelines for investigating global changes over a time scale of decades to centuries. Requirements are given separately for global studies and regional process studies. For global studies, temporal requirements are for sampling every 1 to 12 hours for atmospheric and radiation parameters and 1 day or more for most earth surface measurements. Therefore, the atmospheric measureables provide the most critical drivers for temporal sampling. Spatial sampling requirements vary from 1 km for land and ocean surface characteristics to 50 km for some atmospheric parameters. Thus, the land and ocean surface parameters have the more significant spatial variations and provide the most challenging spatial sampling requirements

ERBE and AVHRR Cirrus cloud fire study

Understanding the impact of cirrus clouds on the global radiation budget is essential to determining the role of clouds in the process of climate change. The ongoing Earth Radiation Budget Experiment (ERBE) is charged with measuring the global radiation balance at the top of the atmosphere. The International Satellite Cloud Climatology Project (ISCCP) is measuring global cloud amounts and properties over a time frame similar to ERBE. Specific cloud properties are absent from the ERBE program, while ISCCP lacks the broadband radiances necessary to determine the total radiation fields. Together, results from these two global programs have the potential for improving the knowledge of the relationship between cirrus clouds and the Earth radiation balance. The First ISCCP Regional Experiment (FIRE), especially its cirrus Intensive Field Observations (IFO), provides opportunities for studying radiation measurements from the ERBE taken over areas with known cirrus cloud properties. Satellite measurements taken during the IFO are used to determine the broadband radiation fields over cirrus clouds and to examine the relationship between narrowband and broadband radiances over various known scenes. The latter constitutes the link between the ERBE and the ISCCP

ATLAS-3 correlative measurement opportunities with UARS and surface observations

The third ATmospheric Laboratory for Applications and Science (ATLAS-3) mission was flown aboard the Space Shuttle launched on November 3, 1994. The mission length was approximately 10 days and 22 hours. The ATLAS-3 Earth-viewing instruments provided a large number of measurements which were nearly coincident with observations from experiments on the Upper Atmosphere Research Satellite (UARS). Based on ATLAS-3 instrument operating schedules, simulations were performed to determine when and where correlative measurements occurred between ATLAS and UARS instruments, and between ATLAS and surface observations. Results of these orbital and instrument simulations provide valuable information for scientists to compare measurements between various instruments on the two satellites and at selected surface sites