AMT paper Nielsen et al. 2022 published

Article

The manuscript "Estimation of refractivity uncertainties and vertical error correlations in collocated radio occultations, radiosondes, and model forecasts" by Nielsen et al. has been published on Atmospheric Measurement Techniques.
 

doi.org/10.5194/amt-15-6243-2022

Short summary

This paper provides a new way to estimate uncertainties and error correlations. The method is a generalization of a known method called the three-cornered hat: Instead of calculating uncertainties from assumed knowledge about the observation method, uncertainties and error correlations are estimated statistically from tree independent observation series, measuring the same variable. The results are useful for future estimation of atmospheric-specific humidity from the bending of radio waves.
 

Title

Estimation of refractivity uncertainties and vertical error correlations in collocated radio occultations, radiosondes, and model forecasts

Authors

Nielsen, J. K., Gleisner, H., Syndergaard, S., and Lauritsen, K. B.

Published

by Atmospheric Measurement Techniques (AMT) at 2022-10-28

Abstract

Random uncertainties and vertical error correlations are estimated for three independent data sets. The three collocated data sets are (1) refractivity profiles of radio occultation measurements retrieved from the Metop-A and B and COSMIC-1 missions, (2) refractivity derived from GRUAN-processed RS92 sondes, and (3) refractivity profiles derived from ERA5 forecast fields. The analysis is performed using a generalization of the so-called three-cornered hat method to include off-diagonal elements such that full error covariance matrices can be calculated. The impacts from various sources of representativeness error on the uncertainty estimates are analysed. The estimated refractivity uncertainties of radio occultations, radiosondes, and model data are stated with reference to the vertical representation of refractivity in these data sets. The existing theoretical estimates of radio occultation uncertainty are confirmed in the middle and upper troposphere and lower stratosphere, and only little dependence on latitude is found in that region. In the lower troposphere, refractivity uncertainty decreases with latitude. These findings have implications for both retrieval of tropospheric humidity from radio occultations and for assimilation of radio occultation data in numerical weather prediction models and reanalyses.
 

Citation

Nielsen, J. K., Gleisner, H., Syndergaard, S., and Lauritsen, K. B.: Estimation of refractivity uncertainties and vertical error correlations in collocated radio occultations, radiosondes, and model forecasts, Atmos. Meas. Tech., 15, 6243–6256, https://doi.org/10.5194/amt-15-6243-2022, 2022.
 

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