Meteorological Support for SOLVE

Meteorological data will be made available in the field for planning aircraft flights and for analyzing aircraft measurements. Data sets from NCEP are available in near-real time, and we anticipate that the data sets from the NASA Goddard Data Assimilation Office (DAO) will also be available to us during the mission period.

Subsetted grids of the three-dimensional gridded fields will be provided in the standard aircraft exchange format for direct use by investigators. These will include data interpolated to the aircraft locations (string files), and vertical profiles along the horizontal flight track (curtain files).

Other data sets which will be available are global conventional radiosonde observations from NCEP and the latest global total ozone maps from the TOMS instrument.

Data products form the Goddard trajectory model will also be available. Back trajectories will be generated from proposed flight tracks to determine whether the parcels to be encountered are expected to have experienced cold temperatures, long periods of darkness, etc.

After each flight, back trajectories from locations along the flight path will be run, and the data will be submitted to the archive in standard exchange file format.

In addition, RDF jobs will be run to produce higher resolution views of the analyses and forecasts in which streamers and fragments of polar and tropical air are more easily traced. The model can be used to generate either isentropic or non-isentropic trajectories, the latter computed using heating rates from a GSFC radiation model. Moreover, because the trajectory model runs fairly quickly on a standard computer workstation, it can be run numerous times to look at different potential temperature levels, different cross-sections, various flight tracks, and so on.

Daily horizontal RDF fields will be generated from the near-real-time forecasts on multiple isentropic surfaces. In addition, we can create RDF vertical cross-sections along any transsection desired to determine the layered, "thin sheet" structure of vortex filaments.

In a similar calculation for tropospheric levels, the time spent by parcels in aircraft high-traffic corridors can be integrated and used to produce maps of aircraft exposure. Such maps were used with success during the October-November 1997 SONEX (SASS Ozone and Nitrogen Oxide EXperiment) deployment over the North Atlantic.

We also propose to generate proximity fields: isentropic maps indicating nearness to parcels which have been sampled by previous aircraft flights or other experiments (e.g., lidars). These can be used to attempt to re-sample air that has been sampled previously.

A mountain-forced gravity wave model, used in previous missions, will be used during SOLVE to forecast regions of potential turbulence at ER-2 altitudes and lower. An improved version of this model, whose use is proposed in a related SOLVE proposal, will be available in the field and make it possible to forecast the appearance of PSCs associated with gravity wave events. We will coordinate with the modeling group appropriately to make these new model data available for mission planning.

The Goddard group is also able to create global hemispheric maps of long-lived trace gas constituents using the quasi-conservative coordinate. Alternatively, the trajectory mapping technique can be used to create such maps. In any case, these can be used for forecasting constituent fields for flight planning or for post-mission data analysis.

All relevant data sets will be transferred to computers in the field. These will include the 3D forecasts and analyses from NCEP and DAO, as well as some conventional data sets, such as radiosonde observations.

The GSFC trajectory model will be run locally in the field, along with the gravity wave model. This will allow for easier and more interactive iterations of flight path design.

Mission scientists and other participants will have access to interactive graphical interfaces for viewing all data products. Horizontal maps on isentropic and isobaric surfaces, vertical cross- sections, zonal means, and raob profiles can all easily be displayed and printed.

Mission and flight planning assistance will be provided via a graphical user interface for use by the project scientist. The software displays meteorological fields (including forecasts) of interest to the user. The flight planner tool can be configured to display restricted airspaces, which are denoted by cross-hatched areas, as well as important landmarks, such as airports capable of handling an ER-2 landing. Thus, this software gives the mission planners an enhanced ability to propose flights to satisfy both scientific and operational constraints. (It is of course not intended to supplant the normal planning procedures by the flight operations crew.)

Data sets from other sources, including other theory teams at SOLVE, can be incorporated easily into the flight planning process as well. Such quantities as advanced gravity wave model results, satellite imagery, parcel exposure to cirrus clouds (time-integrated over trajectories) and air- mass-classified total ozone maps will be coordinated with other groups as appropriate.

By using the analyses and RDFs, we will be able to use the wider dynamical context established by the daily global meteorological analyses to help understand and categorize the data taken. This will be important to interpreting the tracer correlations seen during SOLVE.

Additional uncertainties have been identified by comparing trajectories run with different data sets (e.g., NMC balanced winds, NMC and ECMWF). Where appropriate, trajectories will be run with different data sets.

We will also use the RDF technique to generate detailed, high-resolution fields of potential vorticity. These may be used to examine the effects of mid-latitude air on polar chemistry.

Constituent reconstruction may also be used to compare satellite tracer distributions (such as those measured by UARS instruments) to data taken during SOLVE.