| Summary: | This thesis provides an evaluation of atmospheric H2O measurements at the high Arctic site in Eureka, Nunavut made using ground-based and satellite instruments. The focus is on measurements acquired using a solar absorption Fourier transform infrared spectrometer (the 125HR) located at the Polar Environment Atmospheric Research Laboratory (PEARL), as part of the MUSICA project. Close agreement is observed between H2O total columns from seven PEARL instruments, with mean differences ≤ 1.0 kg/m2 and correlation coefficients (R) ≥ 0.98, except for a comparison between a microwave radiometer and a radiosonde product, which had a correlation coefficient of 0.92. Comparisons revealed a 6% wet bias in the 125HR MUSICA product. Atmospheric Emitted Radiance Interferometer measurements were shown to provide accurate H2O measurements, e.g. within 4% of radiosondes. The PEARL 125HR and Eureka radiosondes were used to demonstrate that the Atmospheric Chemistry Experiment (ACE) satellite instruments, ACE-FTS and ACE-MAESTRO, produce accurate H2O profiles in the upper troposphere and lower stratosphere. ACE-FTS showed a wet bias of up to 6 ppmv (6 to 13%) of 125HR measurements between 6 and 14 km and was within 6 ppmv (12%) of radiosondes between 7 and 11 km. ACE-MAESTRO profiles showed a dry bias relative to the 125HR of between 7% and 12% between 6 and 14 km. ACE data showed closer agreement with the radiosondes and 125HR than did other satellite datasets, e.g. MIPAS, MLS, SCIAMACHY, and TES, except AIRS, which showed mean differences within 5%. In addition, TCCON H2O and δD total column datasets, retrieved from near-infrared 125HR spectra, and not yet assessed in detail, were compared with the well-validated MUSICA products at Eureka and six other globally-distributed sites. The results showed TCCON measurements agree well with MUSICA, although the H2O product had a small dry bias (6%) and the δD had a high bias (40‰). Ph.D.
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