Filters and corrects temperatures from unventilated sensor. This either deletes all air temperature values when the wind speed is below a given threshold or corrects the air temperature data according to "Air Temperature Measurement Errors in Naturally Ventilated Radiation Shields", Reina Nakamura, L. Mahrt, J. Atmos. Oceanic Technol., 22, 2005, pp 1046–1058 with an albedo dependency as introduced in "Albedo effect on radiative errors in air temperature measurements", H. Huwald, C. W. Higgins, M.-O. Boldi, E. Bou-Zeid, M. Lehning, and M. B. Parlange, Water Resour. Res., 45, W08431, 2009.
When correcting the data, the albedo of the surroundings is required as well as the incoming or reflected short wave radiation. If a snow height is available, a generic snow albedo is used when the snow height is above a given threshold, otherwise a soil albedo. This soil albedo can be provided as an option. Moreover, two corrections are available: either HUWALD (Huwald, 2009)[default] or NAKAMURA (Nakamura, 2005). When simply deleting all suspicious air temperatures (SUPPR), the wind speed threshold must be provided.
- Note
- This filter can ONLY be applied to air temperatures. Moreover, since it might depend on the radiation shield, it is highly recommended to do some tests (ie. comparisons between ventillated and unventillated sensors) before using it on a new sensor type. Hopefully a new paper would come and clarify its usability per sensor types...
#using (Huwald, 2009) with default soil albedo
TA::filter2 = unventilated_T
#using (Nakamura, 2005) with specified soil albedo
TA::filter2 = unventilated_T
TA::arg2 = Nakamura 0.23
#simply deleting all values when VW<3. m/s
TA::filter2 = unventilated_T
TA::arg2 = suppr 3.
- Author
- Mathias Bavay
- Date
- 2012-05-03