 The Dvorak technique ( developed between 1969 and 1984 by Vernon Dvorak ) is a widely used system to estimate tropical cyclone intensity ( which includes tropical depression , tropical storm , and hurricane / typhoon / intense tropical cyclone intensities ) based solely on visible and infrared satellite images . Within the Dvorak satellite strength estimate for tropical cyclones , there are several visual patterns that a cyclone may take on which define the upper and lower bounds on its intensity . The primary patterns used are curved band pattern ( <unk> @-@ <unk> ) , shear pattern ( <unk> @-@ <unk> ) , central dense overcast ( CDO ) pattern ( T2.5 @-@ <unk> ) , central cold cover ( CCC ) pattern , banding eye pattern ( <unk> @-@ <unk> ) , and eye pattern ( <unk> - T8.0 ) . 
