Precipitable water is the depth of water in a column of the atmosphere, if all the water in that column were precipitated as rain. As a depth, the precipitable water is measured in millimeters or inches. Often abbreviated as "TPW", for Total Precipitable Water.
Measurement
There are different measurement techniques:
One type of measurement is based on the measurement of the solar
irradiance on two wavelengths, one in a water absorption band, and the other not. The precipitable water column is determined using the irradiances in these bands and the
Beer–Lambert law.
Some work has been performed to create empirical relationships between surface
specific humidity and precipitable water based on localized measurements (generally a 2nd to 5th order polynomial).[2][3][4] However, this method has not received widespread use in part because humidity is a local measurement and precipitable water is a total column measurement.
References
^Bevis, M.; et al. (1992). "GPS Meteorology: Remote Sensing of Atmospheric Water Vapor Using the Global Positioning System". Journal of Geophysical Research. 97 (D14): 15787–15801.
Bibcode:
1992JGR....9715787B.
doi:
10.1029/92JD01517.
^Hsu, S.A.; Blanchard, B.W. (15 October 1989). "The Relationship Between Total Precipitable Water and Surface-Level Humidity Over the Sea Surface: A Further Evaluation". Journal of Geophysical Research. 94 (C10): 14539–14545.
Bibcode:
1989JGR....9414539H.
doi:
10.1029/JC094iC10p14539.
Precipitable water is the depth of water in a column of the atmosphere, if all the water in that column were precipitated as rain. As a depth, the precipitable water is measured in millimeters or inches. Often abbreviated as "TPW", for Total Precipitable Water.
Measurement
There are different measurement techniques:
One type of measurement is based on the measurement of the solar
irradiance on two wavelengths, one in a water absorption band, and the other not. The precipitable water column is determined using the irradiances in these bands and the
Beer–Lambert law.
Some work has been performed to create empirical relationships between surface
specific humidity and precipitable water based on localized measurements (generally a 2nd to 5th order polynomial).[2][3][4] However, this method has not received widespread use in part because humidity is a local measurement and precipitable water is a total column measurement.
References
^Bevis, M.; et al. (1992). "GPS Meteorology: Remote Sensing of Atmospheric Water Vapor Using the Global Positioning System". Journal of Geophysical Research. 97 (D14): 15787–15801.
Bibcode:
1992JGR....9715787B.
doi:
10.1029/92JD01517.
^Hsu, S.A.; Blanchard, B.W. (15 October 1989). "The Relationship Between Total Precipitable Water and Surface-Level Humidity Over the Sea Surface: A Further Evaluation". Journal of Geophysical Research. 94 (C10): 14539–14545.
Bibcode:
1989JGR....9414539H.
doi:
10.1029/JC094iC10p14539.