B05: Variability and trends of water vapour in the Arctic
Water vapour being the strongest greenhouse gas is a key candidate for contributing to Arctic amplification. However, as shown in phase I of (AC)³ the lack of widespread reference water vapour observations together with its pronounced temporal and regional variability hampers a firm assessment of the role of water vapour for Arctic amplification. In the past a robust positive trend in integrated water vapour (IWV) from reanalyses could only be revealed for few regions and seasons. The pronounced spatial patterns can not be captured by the classical radiosonde network, which requires satellite measurements. Embedded in the Global Energy and Water Exchanges (GEWEX) Water Vapour Assessment (G-VAP) a comparison of different integrated water vapour products including the satellite product developed in B05 revealed large differences for the central Arctic, which we will investigate making use of the detailed observations during MOSAiC from the ground and by aircraft. In the Arctic, microwave satellite IWV retrievals are complicated by the strong emission of sea ice compared to ocean. Therefore, a new optimal estimation retrieval scheme will be developed that simultaneously retrieves sea ice characteristics and water vapour plus liquid water path information. Microwave radiometer (MWR) observations of snow and sea ice from the ground to be collected during MOSAiC will support the development. Similarly, a novel high frequency MWR operated on board RV Polarstern will serve as a reference for IWV measurements in the Arctic. The impact of water vapour on downward thermal-infrared radiation depends on the vertical distribution of moisture which is even more difficult to assess than IWV. Here we will make use of multi-spectral, ground–based MWR measurements, possibly combined with satellite measurements, to assess moisture inversions, which are of high importance in sustaining mixed-phase
clouds. The effect on downward thermal-infrared radiation will be investigated by taking the role of LWP into account, which is retrieved along with IWV.
The observations from the ground, aircraft, and satellite will be used to validate existing and upcoming reanalyses, e.g., ERA5, Arctic System Reanalysis (ASR), and the emerging Copernicus reanalysis. Special emphasis will be put on extreme events like atmospheric rivers in cooperation with E04, which are highly variable.
The consideration of temporal and regional variability of water vapour is necessary to establish the role of water vapour for Arctic amplification.
Specifically we want to answer the following questions:
- Does an improved consideration of surface emission improve satellite water vapour retrievals such that quantifying the water vapour feedback in the Arctic becomes possible?
- Can we explain the strong water vapour differences between water vapour products (reanalyses, satellites) using the reference measurements from the MOSAiC and HALO–(AC)³ campaigns?
- Do new satellite instruments have the potential to provide the needed information on water vapour profiles to assess the water vapour impact on downward thermal-infrared radiation?
Achievements phase I
In B05, new retrieval techniques to derive the Integrated Water Vapour (IWV) from satellite have been developed allowing continuous measurements of IWV fields over the ocean and sea ice by merging observations from different microwave satellite sensors (Scarlat et al., 2017; Triana Gómez et al., 2018; Triana Gómez et al., submitted 2019). A quantification of the uncertainty of trends in total water vapour based on reanalysis was performed (Rinke et al., 2019). Simulations of microwave brightness temperature for polar lows were carried out. Furthermore, an evaluation of IWV from satellite products, reanalyses, and HIRHAM simulations was done for the ACLOUD campaign. Also, an investigation of the relationship between IWV and thermal-infrared downward radiation in reanalyses and models was performed for the period of 1979-2016.
Role within (AC)³
Dr. Gunnar Spreen
University of Bremen
Institute of Environmental Physics (IUP)
Dr. Annette Rinke
Alfred-Wegener-Institute Helmholtz-Center for Polar and Marine Research (AWI)
Dr. Kerstin Ebell
University of Cologne
Institute for Geophysics and Meteorology (IGM)
Prof. Dr. Susanne Crewell
University of Cologne
Institute for Geophysics and Meteorology (IGM)
Rinke, A., B. Segger, S. Crewell, M. Maturilli, T. Naakka, T. Nygaard, T. Vihma, F. Alshawaf, G. Dick, and J. Wickert, and J. Keller, 2019: Trends of vertically integrated water vapor over the Arctic during 1979-2016: Consistent moistening all over? J. Clim., 32, 6096-6116, doi:10.1175/JCLI-D-19-0092.1
Triana Gómez, A., G. Heygster, C. Melsheimer, and G. Spreen: Improved Water Vapour retrieval from AMSU-B/MHS in polar regions, submitted to Atmos. Meas. Tech. Discuss.,doi:10.5194/amt-2019-253
Radovan A., S. Crewell, E.M. Knudsen, and A. Rinke, 2019: Environmental conditions for polar low formation and development over the Nordic Seas: study of January cases based on the Arctic System Reanalysis, Tellus A, 71 (1), 1-16, doi:10.1080/16000870.2019.1618131
Wendisch, M., A. Macke, A. Ehrlich, C. Lüpkes, M. Mech, D. Chechin, K. Dethloff, C. Barrientos, H. Bozem, M. Brückner, H.-C. Clemen, S. Crewell, T. Donth, R. Dupuy, C. Dusny, K. Ebell, U. Egerer, R. Engelmann, C. Engler, O. Eppers, M. Gehrmann, X. Gong, M. Gottschalk, C. Gourbeyre, H. Griesche, J. Hartmann, M. Hartmann, B. Heinold, A. Herber, H. Herrmann, G. Heygster, P. Hoor, S. Jafariserajehlou, E. Jäkel, E. Järvinen, O. Jourdan, U. Kästner, S. Kecorius, E.M. Knudsen, F. Köllner, J. Kretzschmar, L. Lelli, D. Leroy, M. Maturilli, L. Mei, S. Mertes, G. Mioche, R. Neuber, M. Nicolaus, T. Nomokonova, J. Notholt, M. Palm, M. van Pinxteren, J. Quaas, P. Richter, E. Ruiz-Donoso, M. Schäfer, K. Schmieder, M. Schnaiter, J. Schneider, A. Schwarzenböck, P. Seifert, M.D. Shupe, H. Siebert, G. Spreen, J. Stapf, F. Stratmann, T. Vogl, A. Welti, H. Wex, A. Wiedensohler, M. Zanatta, S. Zeppenfeld, 2019: The Arctic Cloud Puzzle: Using ACLOUD/PASCAL Multi-Platform Observations to Unravel the Role of Clouds and Aerosol Particles in Arctic Amplification, Bull. Amer. Meteor. Soc., 100 (5), 841–871, doi:10.1175/BAMS-D-18-0072.1
Knudsen, E.M., B. Heinold, S. Dahlke, H. Bozem, S. Crewell, I. V. Gorodetskaya, G. Heygster, D. Kunkel, M. Maturilli, M. Mech, C. Viceto, A. Rinke, H. Schmithüsen, A. Ehrlich, A. Macke, C. Lüpkes, M. Wendisch, 2018: Meteorological conditions during the ACLOUD/PASCAL field campaign near Svalbard in early summer 2017, Atmos. Chem. Phys., 18, 17995-18022, doi:10.5194/acp-18-17995-2018
Triana Gómez, A., G. Heygster, C. Melsheimer, and G. Spreen, 2018: Towards a Merged Total Water Vapour Retrieval from AMSU-B and AMSR-E Data in the Arctic Region, Proceedings of the “IGARSS 2018 – 2018 IEEE International Geoscience and Remote Sensing Symposium,” IEEE, Valencia, 1818–1821, doi:10.1109/igarss.2018.8517863
Scarlat, R. C., C. Melsheimer, and G. Heygster, 2018: Retrieval of Total Water Vapour in the Arctic Using Microwave Humidity Sounders, Atmos. Meas. Tech., 11, 2067-2084, doi:10.5194/amt-11-2067-2018
Küchler, N., S. Kneifel, U. Löhnert, P. Kollias, H. Czekala, and T. Rose, 2017: A W-band radar-radiometer system for accurate and continuous monitoring of clouds and precipitation, J. Atmos. Oceanic Technol., doi:10.1175/JTECH-D-17-0019.1
Bühl, J., Alexander, S., Crewell, S., Heymesfield, A., Kalesse, H., Khain, A., Maahn, M., van Tricht, K., Wendisch, M., 2017: Ice Formation and Evolution in Clouds and Precipitation: Measurement and Modeling Challenges, Baumgardner, D., McFarquhar, G., and Heymsfield, A. (Eds.), Chapter 10: Remote Sensing, AMS Meteorological Monographs, 58, 10.1-10.21, doi:10.1175/AMSMONOGRAPHS-D-16-0015.1