Significance and Use

Atmospheric pressure is one of the basic variables used by meteorologists to describe the state of the atmosphere.

The measurement of atmospheric pressure is needed when differences from standard pressure conditions must be accounted for in some scientific and engineering applications involving pressure dependent variables.

These methods provide a means of measuring atmospheric pressure with the accuracy and precision comparable to the accuracy and precision of measurements made by governmental meteorological agencies.

1. Scope

1.1 These methods cover the measurement of atmospheric pressure with two types of barometers: the Fortin-type mercurial barometer and the aneroid barometer.

1.2 In the absence of abnormal perturbations, atmospheric pressure measured by these methods at a point is valid everywhere within a horizontal distance of 100 m and a vertical distance of 0.5 m of the point.

1.3 Atmospheric pressure decreases with increasing height and varies with horizontal distance by 1 Pa/100 m or less except in the event of catastrophic phenomena (for example, tornadoes). Therefore, extension of a known barometric pressure to another site beyond the spatial limits stated in 1.2 can be accomplished by correction for height difference if the following criteria are met:

1.3.1 The new site is within 2000 m laterally and 500 m vertically.

1.3.2 The change of pressure during the previous 10 min has been less than 20 Pa.

The pressure, P ₂ at Site 2 is a function of the known pressure P ₁ at Site 1, the algebraic difference in height above sea level, h ₁ ? h ₂ , and the average absolute temperature in the space between. The functional relationship between P ₁ and P ₂ is shown in 10.2. The difference between P ₁ and P ₂ for each 1 m of difference between h ₁ and h ₂ is given in Table 1 and 10.4 for selected values of P ₁ and average temperature.

1.4 Atmospheric pressure varies with time. These methods provide instantaneous values only.

1.5 The values stated in SI units are to be regarded as the standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific safety precautionary statements are given in Section 7.

TABLE 1 Selected Values

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D1356 Terminology Relating to Sampling and Analysis of Atmospheres

D3249 Practice for General Ambient Air Analyzer Procedures

IEEE/ASTM SI 10 Standard for Use of the International System of Units (SI): The Modern Metric System

Keywords

aneroid barometer; atmospheric pressure; barometer; barometry; Fortin-type mercurial barometer; mercurial barometer; pressure: Aneroid barometers; Atmospheric analysis--meteorological measurements; Barometric measurement; Fortin-type mercurial barometers; Meteorological conditions/tests; Pressure testing; Surface analysis--atmospheric;

ICS Code

ICS Number Code 07.060 (Geology. Meteorology. Hydrology)

DOI: 10.1520/D3631-99R11

ASTM International is a member of CrossRef.

ASTM D3631