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| RAMMB CIRA 1st Quarter Report FY2008 |
October November December |
A new study has begun which involves using GOES-11 bands 4 and 5 to assist in retrieving boundary layer moisture depth. Eleven sounding locations were selected across the central plains of the U.S., and raob data from the summers of 2006 and 2007 were collected. GOES data was also obtained so that comparisons can be made between the raob water vapor profiles and the GOES brightness temperatures at those locations. Preliminary results are promising. (D. Lindsey)
A paper entitled "Indication of water vapor transport into the lower stratosphere above midlatitude convective storms: Meteosat Second Generation satellite observations and radiative transfer model simulations," by M. Setvak, D. Lindsey, R. Rabin, P. Wang, and A. Demeterova was accepted for publication in Atmospheric Research. (D. Lindsey)
A manuscript entitled "The stratospheric impact of the Chisholm pyrocumulonimbus eruption: Part I, earth-viewing satellite perspective," by M. Fromm, O. Torres, D. Diner, D. Lindsey, B. Vant Hull, R. Servranckx, E. P. Shettle, and Z. Li, was accepted for publication in the Journal of Geophysical Research. (D. Lindsey)
A paper entitled "Satellite Detection of Severe Convective Storms by their Retrieved Vertical Profiles of Cloud Particle Effective Radius and Thermodynamic Phase," by D. Rosenfeld, W. Woodley, A. Lerner, G. Kelman, and D. Lindsey was accepted to the Journal of Geophysical Research. (D. Lindsey)
Preliminary results of a study assessing the relationship between positive-lightning-dominated storms and satellite-retrieved cloud-top ice crystal size are encouraging. Using GOES data as well as data from the National Lightning Detection Network (NLDN) from the summer of 2007, thunderstorms occurring in and around the state of Kansas were analyzed by examining their lightning polarity and ice effective radius. Figure 1 below generally shows that the regions with more positive storms (defined as >25% positive cloud-to-ground lightning) tend to have smaller cloud-top effective radii, although the relationship is not perfect. This suggests that there may be a link between the physical mechanisms determining thunderstorm polarity and cloud-top ice crystal size. This work is being presented as a poster at the annual AMS Meeting in New Orleans in January 2008. (D. Lindsey)
Figure 1. Number and percentage of positive (defined as >25% positive cloud-to-ground strikes) and negative storms, and the average GOES-retrieved ice effective radius for those storms, during the summer of 2007 in 8 geographic regions in and near Kansas.
Henry’s Rule states that a stationary trough over the southwestern U.S. will begin to lift out when an upstream shortwave travels to 2200 km from the stationary trough. Because water vapor imagery is useful in tracking upper tropospheric waves, it will be examined to see if it can be applied to Henry’s rule. Upper-air analyses for the 2005-2006 and 2006-2007 seasons were examined and a number of cases selected for further analysis. GOES data and GFS model analyses have begun to be collected for these cases. (J. Dostalek)
As part of the project to develop a quantitative measure of central surface pressure of midlatitude cyclones over the eastern Pacific Ocean from satellite imagery, background reading on neural networks has begun, as well as the collection of surface pressure data which will be used for initial case identification. (J. Dostalek)
The GIMPAP project concerning the research of the warm sector of wintertime midlatitude cyclones has been handed to CSU student Darren Van Cleave as his Masters’ Thesis. Discussions about the research and McIDAS training for Darren have taken place. (J. Dostalek)
A three-year project entitled “Polar Winds from Satellite Imagers and Sounders” has been completed. It was a multi-agency effort investigating the use of satellites to provide wind information over the Polar regions, an area with few surface and radiosonde stations. The RAMMB contribution was to use temperature profiles derived from AMSU-A radiances, along with the assumption of hydrostatic and dynamic balance (geostrophic, linear, and nonlinear), to estimate the wind field. Figures 2 and 3 show the wind speed bias and vector root mean square error (with respect to collocated radiosondes) as a function of pressure for a winter and a summer dataset, respectively. For the entire depth of the atmosphere the three balances had biases between -0.7 and -1.0 m s-1 and root mean square errors between 6 and 7 m s-1. A final report was sent to Jeff Key of CIMSS, who was the PI of the project. (J. Dostalek)
Figure 2. Wind speed bias and vector RMSE between the winds derived using the AMSU radiances and collocated radiosondes for the winter 2004 dataset. Solid lines are the bias and dashed lines are the RMSE, with the exception of the solid blue line, which is the mean radisonde-derived wind speed. The colors correspond to the different balance approximations. The number of comparisons at each level is given on the right hand side of the figure.
Figure 3. Same as Figure 2, but for the summer 2007 dataset.
Processing of the large sector U.S. climatologies continues. Products completed include monthly large sector composites for September and October 2007. The processing should be back on schedule next quarter. (C. Combs)
Processing of wind regime products continues. Monthly wind regime composites from both channel 1 and channel 4 for August, September, and October 2007 have been completed. Combined monthly products have also been completed for August, September and October 2007. (C. Combs)
Preprocessing of GOES west data over the Eureka area continues. May 1999-2006 and September 1998-2005 have been processed. Routines and code changes for processing GOES 11 data have been completed. In additions, procedures for processing and quality control for hours not normally processed, but in our DVD archive, have been completed. This is required to study marine stratus on an hourly basis instead of the current every other hour. Aug-Sept 2003, May-Sept 2004, and May-Jun 2005 of these in-between hours have been completed. (C. Combs)
A meeting to discuss incorporating the wind regime cloud climatologies into the Cheyenne’s National Weather Service (NWS) office forecast process was held in Cheyenne, WY. Science and Operations Officer, Melissa Goering, Information and Technology Officer, Ray Gomez from Cheyenne, and Deb Molenar and Cindy Combs from CIRA attended. A plan was developed to include the cloud climatologies in Cheyenne’s Graphical Forecast Editor (GFE) for a first guess in cloud cover forecast. It will be tested on CIRA’s GFE before transferring to Cheyenne. (C. Combs)
The software to generate three-color (RGB – red, green, blue) images, and to produce a McIDAS AREA file, has been sent to Dr. Randall Alliss, Atmospheric Effects Manager at Northrop Grumman in Chantilly VA. Alliss requested the program from Don Hillger during discussions at the 2007 McIDAS Users’ Group meeting. The CIRA-developed program is unique in that it creates a single 8-bit McIDAS AREA, one that can be easily looped within McIDAS, instead of a 24-bit JPG image that is the output of the McIDAS application titled COMBINE. (D. Hillger)
The latest version of software for Principal Component Image (PCI) analysis has been sent to Matthew Lazzara at UW/CIMSS. The updated software includes some changes needed to facilitate the use of the code by outside users. The code will be used to study fog in the Antarctic using MODIS data. This study, initiated a few years ago, is being pursued as research towards a PhD for Mr. Lazzara. Mr. Lazzara will also help standardize the help files for the code so that it can be made available as McIDAS experimental code for other potential users. (D. Hillger)