LEARNING OBJECTIVES: Define the DVAL program. Recognize program inputs. Identify applications, limitations, and assumptions. Explain an example of the D-value profile. The DVAL program is used to compute profiles of D-values. A D-value is defined as the difference between the actual height above mean sea level (MSL) of a particular isobaric surface and the height of the same pressure surface in the U.S. Standard Atmosphere. Program input consists of temperature and geopotential height profiles with respect to pressure, output altitude increment, and specification of units for which the output is desired.

D-values are used by naval aviators to make pressure-bomb detonation altitude corrections.

Figure 7-1.-Example output of the ECM effectiveness display.

The restrictions as well as the principles taken for granted in using the DVAL program areas follows:

. The algorithm used by this program applies to a maximum altitude of 11,000 geopotential meters.

. The D-value for MSL is determined by extrapolating the pressure and temperature data to MSL by using the data for the first two levels of the entered environmental profile. Caution should be exercised in determining over-water surface D-values using radiosonde data from a coastal location when the balloon-release height is >50 meters.

AD-value is defined as a difference in the observed height of a particular isobaric surface and the height associated with that isobaric surface in the U.S. Standard Atmosphere. Table 7-1 shows an example of the D-value profile.

Table 7-1.-Example Output of the D-Value Profile

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