SHEBA Surface Flux Group
Future Plans

MINUTES OF THE SHEBA ATMOSPHERIC SURFACE FLUX GROUP MEETING Dallas, Texas, Tuesday, 12 January 1999 DATA PROCESSING For profile analysis and turbulence scaling, we need to know instrument heights on the main tower. Ed will obtain the Pittsburgh snow depth data from Don Perovich and correct the winter sensor heights. The product will be a series of corrected tower instrument heights for the entire year. We did several instrument intercomparisons through the year both with the Vaisala wand and by using the tower elevators. Peter will take the lead in evaluating these intercomparisons. In particular, he will incorporate the TRH sensor intercalibrations being done at NCAR and will also try to evaluate whether flow through the tower affected the average wind speed and TRH values. What the surface temperature is is still a major issue.Ed (perhaps with the help of Kerry Claffey) will continue the analysis of the surface temperature instruments and try to develop a single best-surface-temperature value for the entire year. In particular, we may be able to use tower temperature profiles in neutral stratification to infer the surface temperature and then tune the radiative measurements to give the same result. Some reprocessing and some additional processing are necessary. In particular, we need to compute latent heat fluxes from the Ophir data, compute higher-order turbulence statistics to evaluate terms in the kinetic-energy and scalar-variance budgets, and compute hourly averaged spectra, cospectra, and quadrature spectra. We also need a file with the hourly averaged relative humidity data (with respect to water, the measured quantity). Ola, Chris, and, possibly, Afshan Alam will be responsible for this reprocessing. To compute fluxes, spectra, cospectra, and quadrature spectra from the tower data, we will average for 13+ minutes (presumably, 8192 samples) and simply sum these 13-minute covariances or spectra to get hourly averages. In other words, the tower data will be effectively filtered at 13+ minutes. Because the PAM data are averaged in 5-minute blocks, to create comparable averages, Tom Horst and crew will extend the 5-minute averages to 15-minute averages by adding the variances and covariances of the 5-minute averages of u, w, and t to the 5-minute averages. They will then sum these 15-minute values to produce hourly averages comparable to the tower data. In other words, the PAM data will have a 15-minute filter. COLLABORATIONS At present, we are collaborating with two groups outside our own circle on analyses based on our data. Jim Pinto wants the PAM data to study the horizontal variability of the radiative fluxes. Tom Horst can give him that data. At least one of us will also be a co-author of any paper that results. Tony Beesley and Chris Bretherton have used our November data from the web to compare ECMWF forecasts with actual SHEBA conditions. Ed will supply them radiative and sensible heat flux data for the rest of the year so they can extend their analysis. Again, we will explain to them that they do not have permission to give our data to anyone else. Ed will also be the designated co-author of their paper. REPORTING Web Site Peter will maintain a web site at NPS with pertinent photos from the experiment. In particular, he will create several panoramas depicting the ice conditions throughout the experiment. He will also prepare a chronological sequence of photos of each PAM site. If you have either panoramas or pictures of the PAM sites, send prints to Peter with information as to the date and the site. Journal Article Ola and Chris will take the lead in preparing a descriptive article documenting conditions during our SHEBA year with JGR or Journal of Climate being the target. Preliminary Report Ed will prepare a preliminary report of our efforts by simply collecting all the SHEBA papers we presented in Dallas and binding them together. He may or may not write a brief introduction. (Anyone so moved may also write this inroduction.) I anticipate sending you each 15 copies of this. Here are the papers that I will include in this report. Did I miss any? When you receive reprints from AMS, please send me copies to use as masters for this volume.

Here is the list of Publications and Conference Presentations

ANALYSIS PRIORITIES Last month, we circulated lists of preferred analysis objectives. (I did not receive one from Ola, though; I think he was on vacation when this was going on.). Here is that wish list in no special order, with lead analysts noted. 1. Paper on relative humidity evaluated with respect to ice (Ed). 2. Studies based on the scintillometer (Ed). 3. Studies of Monin-Obukhov similarity theory (Ed, Peter, Chris). 4. Bulk-transfer coeffcients evaluated from both tower and PAM data (Chris, Ed, Peter). 5. Spatial variability of terms in the surface heat budget (Ed, Peter). 6. Evaluating the von Kármán constant (Ed, Peter)? 7. Vertical variability of the tower fluxes, which complements item 3 (Peter). 8. Cloud-radiation-albedo feedback (Peter, Ola). 9. Spectral and cospectral analysis and structure parameters (Chris, Ed). 10. TKE and scalar-variance budgets and higher-order statistics (Chris, Ed). Here is Ola's input: The following are analyses I would like to do with the SHEBA data: 1) Complete the analysis of the annual surface heat budget and interact with D. Perovich. 2) Continue examination of relation of surface heatbudget terms to larger-scale forcing - cloud-radiation-albedo feedback - interactions with T. Uttal, J.Intrieri, & C. Bretherton (?) 3) Examine spatial variability of terms in surface heat budget - interact with J. Overland for satellite remote sensing in wintertime 4) Evaluate bulk transfer coefficients from both tower and PAM data -interact with other ASFG PIs 5) Examine relative importance of turbulent and radiative heat transport to the surface from the inversion top - involve analyzing sodar, aircraft,radar, lidar, radiosounding and tower radiometer data - should produce a fairly complete picture of Arctic boundary layer structure 6) Complete poster for radiation conference for C. Russell's presentation 7) Analyze the case of rapid surface ozone changes - interact with Alexandre Makshtas (St.Petersburg) 8) Produce a photo album of tower and PAM stations throughout the year This is an ambitious list of analyses, especially considering the data processing still necessary and the relatively small level of funding still available. Hence, I will consider it a very successful year if the data processing items get done and analysis items 1), 2), 6), and 7). Item 8) is something I might be able to get assistance with. I expect that I will contribute to two general SHEBA descriptive papers (EOS, BAMS) and probably be the lead author on a paper describing the ASFG data set and on one describing the impact of the synoptic and mesoscale on the surface energy budget components in the Arctic. I also expect to give several presentations on SHEBA during the year, starting with a talk at ETL and two invited talks in Scandinavia in April. Adeline Wong's work is related to my analyses 1) , 2) and 3) above, so I certainly don't want to just give her the data and be acknowledged, either. I would like to be involved as an author as well. In fact, I will soon be starting on a journal paper related to item 2 (e.g., to my IOS SHEBA paper in Dallas --surface thermal response to clouds.)

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Last update: 5/5/99
Please send all comments and suggestions to the author, Peter Guest,