Tuesday, 11 February 2003: 8:45 AM
An improved land/ocean dust enhancement applicable to MODIS
Navy operations over data-denied regions of the world rely heavily on model and remote sensing meteorological guidance in making critical tactical decisions. Unexpected environmental conditions in the operating arena can spell any number of undesirable outcomes ranging from mission aborts (leading to millions of taxpayer dollars lost in wasted munitions) to mishaps and loss of life. Central to the meteorological challenges confronted during Operation Enduring Freedom were frequent, pervasive, and long-lasting desert dust storms spanning over both land and ocean. These storms posed considerable problems to operations in terms of visibility reduction--below 1 nautical mile in the more extreme events. While conventional satellite infrared (IR) and visible (VIS) imagery based techniques are capable of identifying dust to a marginal extent, ambiguity over the often laminar and highly reflective desert backgrounds compromises their utility.
The current research builds upon previous efforts to enhance dust-over-water using multi-spectral Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data, extending this capability to dust-over-land by virtue of the additional spatial and spectral information afforded by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Earth Observing System (EOS) Terra and Aqua platforms. The method, which is composed of two separate algorithms for treatment of over-land and over-water, goes a step beyond previous VIS/IR methods in discriminating elevated dust from cloud features. The data are presented in a way that preserves the appearance of the enhancement across coastal (and algorithmic) interfaces, and includes sun-glint masking. Strengths, limitations, and examples of this new approach are provided and compared against previous methods.