Task Title: LST Diurnal Analysis (Diurnal)
Staff: Konstantin Vinnikov, Senior research Scientist
Institute: University of Maryland/ Department of Atmospheric and Oceanic Science/ CICS
Period of Performance: 1 July 2012 – 30 June 2013
- Description of the Task:
Current work on developing algorithm for correcting GOES-R retrieved clear Sky Land Surface Temperature will be continued during the next period. We postulate that there are two main kernels in the angular anisotropy of LST. The first of them, related to angular anisotropy of land surface absorbed solar radiation, manifests itself in the daytime LST data, only. Effect of shadows is the main component of this kernel and it depends on satellite viewing and solar, zenith and relative azimuth, angles. The other kernel manifests itself in the nighttime dependence of LST on viewing zenith angle and is caused by angular dependences of broadband infrared land surface emissivity and atmospheric infrared radiation. It is analogous to land surface limb darkening phenomenon. This effect can be studied using nighttime LST observations when it can be distinguished from the daytime shadowing effect. The infrared kernel works also in the daytime, when its effect is superimposed on the solar kernel. It is expected that the current period of this project will be completed with developing the first prototype of the algorithm for angular correction of GOES-R satellite retrieved LST. This algorithm should adjust observed LST to LST at viewing zenith angle equal to zero (observation in the nadir). Angular correction should be also included in the GOES-R LST validation algorithm. The approach, the kernels, parameterizations, structure of the algorithm, strategy of its application should be enhanced and tested using independent data during the next period of work. The next data set is going to be used in the planned work.
- Data:
GOES Surface and Insolation Products (GSIP) contains GOES-E and GOES-W LST retrievals with temporal resolution of one hour and spatial resolution of 1/8 degree (~14km). Data from GOES-E has a 15-minute shift compared to GOES-W data. No angular correction is included into the LST retrieval algorithm. One full year of observation (May 2010-April 2011) for Northern Hemisphere Extended Scan Sectors of satellites GOES-13 (EAST) and GOES-11 (WEST) will be obtained from the CLASS/NOAA web site http://www.class.noaa.gov/ .
Systematic, but seasonally/diurnally distributed LST error resulted from the 15-minute shift in observation time of two satellites. This error has the same order of magnitude as effect of angular anisotropy. To be comparable, LST observed by GOES-13, will be interpolated into the observation times of GOES-11. This should be done at each spatial grid at each time. Mean diurnal and seasonal variations of LST will be evaluated and taken into account in the interpolation algorithm.
- Schedule and milestones (in bold)
3.1.Collect and quality control full year of overlapping GOES-11 and GOES-13 GSIP archived LST data for Northern Hemisphere Extended Scan Sectors. Adjust GOES-13 LST data to GOES-11 times of observation. July 1, 2012 - September 30, 2012.
3.2.One year GOES-13 LST data set adjusted to GOES-11 times of observation. September 1, 2012 – September 30, 2012.
3.2.Validate and improve parameterization of IR limb darkening kernel in the empirical model of LST angular anisotropy using nighttime overlapping observations of GOES-11 and GOES-13. September 1, 2012 - December 31, 2012.
3.3.Validate and improve parameterization of solar radiation related kernel in the empirical model of LST angular anisotropy using daytime overlapping observations of GOES-11 and GOES-13. December 31, 2012 - March 31, 2013.
3.4.Evaluation of accuracy of proposed LST angular anisotropy correction algorithm. March 1, 2013 – March 31, 2013.
3.5.Accomplish experimental blending historical GSIP GOES-11 and GOES-13 LST data using proposed algorithm for LST angular anisotropy correction. April 1, 2013 - June 30, 2013.
3.6.Conclusion on usefulness and recommendation on blending LST data retrieved from GOES-E and GOES-W satellites. June 1, 2013 – June 30, 2013.
- Fund request and budget plan
Fund request for FY12: $ 105 K/yr
Work will be performed by Konstantin Vinnikov, 40% of his time (12 months). Budget plan: $ 8.75 K/month.