Estimating COCOM Natural Background Dormancy
ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
Pagination or Media Count:
Seasonal change, expressed as phenological stage, controls color and texture of natural vegetation as it cycles through greenup, verdancy, senescence, and dormancy. For the Army Product Manager Soldier Clothing and Individual Equipment PM SCIE Phase IV Camouflage Effort, we quantitatively estimated the number of days between the onset of dormancy and the onset of greenup in 25 countries over a wide range of climates and latitudes. Global land cover was lumped into Arid, Transitional, and Woodland types and dormant periods were determined for the latter two cover types. Phenological stage transition dates were mapped from the 500 m resolution MODIS Land Cover Dynamics Product Friedl 2012a derived from the Enhanced Vegetation Index. We found that the mean length of dormancy MLD varies with climate and with cover type. Higher latitude seasonal change is predominantly thermally controlled, and lower latitude change is predominantly moisture-controlled. Thermally controlled seasons exhibit less-variable MLDs than moisture-controlled seasons. It is unclear exactly what our results mean with regard to plant appearance as few validation field studies have been conducted in many climate and cover types. Considering the scale of the analysis and the desired generalization of the results, our study resulted in reasonable MLD values.
- Anatomy and Physiology
- Optical Countermeasures