Figure: Airborne remote sensing over the tropical Atlantic. Insights into vertical cloud structure and water content from active and passive microwave observations. The colorful lines show all flight tracks where HAMP was used in the tropics. The dots below show an example model output of LWP that is used for retrieval development and assessment. The time series are an example of liquid (LWP) and rain water path (RWP) retrieval products and radar reflectivity profiles.

Representation of cloud and precipitation processes is one of the largest sources of uncertainty in climate and weather predictions. This project aims at exploring the potential of the novel HALO microwave package (HAMP) for airborne cloud and precipitation research by participating in all cloud related missions of the research aircraft HALO. HAMP is a unique combination of a 26 channel microwave radiometer and a cloud radar. To make HAMP a valuable research instrument, we will develop synergistic retrieval algorithms which convert the measured passive and active microwave signals into profiles of temperature, humidity and hydrometeor content with corresponding error estimates. A comprehensive evaluation of HAMP with existing observational systems, like e.g. satellites and ground based remote sensing super-sites will allow an assessment of its added value. In particular, we will analyze whether HAMP can resolve the fine-scale structure of cloud and precipitation fields and can thus relate point observations with area averaged data from satellites and models. Finally, observations from the NARVAL campaign will be used to demonstrate the benefit of HAMP for model development by revising the frequently used model assumption that shallow convective clouds do not precipitate.

• Validation of satellite estimates of cloud properties and precipitation by performing detailed in situ and remote sensing observations of cloud vertical structure
• Perform process studies on cloud and precipitation for evaluating and improving cloud parameterizations in weather forecast and climate models

• Ebell, K., E. Orlandi, A. Hünerbein, U. Löhnert, S. Crewell, 2013: Combining ground and satellite based measurements in the atmospheric state retrieval: Assessment of the information content, J. Geophys. Res. 18, 6940–6956, doi:10.1002/jgrd.50548.

• Jacob, M., F. Ament, M. Gutleben, H. Konow, M. Mech, M. Wirth, and S. Crewell: Investigating the liquid water path over the tropical Atlantic with synergistic airborne measurements, Atmos. Meas. Tech., submitted January, 2019.

• Konow, H., M. Jacob, F. Ament, S. Crewell, F Ewald, M. Hagen, L. Hirsch, F. Jansen, M. Mech, B. Stevens: A unified data set of airborne cloud remote sensing using the HALO Microwave Package (HAMP), Earth System Science Data Discuss., https://doi.org/10.5194/essd-2018-116, in review, 2019.

• Mech, M., E. Orlandi, S. Crewell, F. Ament, L. Hirsch, M. Hagen, G. Peters, and B. Stevens, 2014: HAMP - the microwave package on the High Altitude and LOng range research aircraft HALO, Atmospheric Measurement Techniques, 7, 4623-4657, doi:10.5194/amt-7-4539-2014.

• Schäfler, A., G. Craig, H. Wernli, P. Arbogast, J.D. Doyle, R. McTaggart-Cowan, J. Methven, G. Rivière, F. Ament, M. Boettcher, M. Bramberger, Q. Cazenave, R. Cotton, S. Crewell, J. Delanoë, A. Dörnbrack, A. Ehrlich, F. Ewald, A. Fix, C.M. Grams, S.L. Gray, H. Grob, S. Groß, M. Hagen, B. Harvey, L. Hirsch, M. Jacob, T. Kölling, H. Konow, C. Lemmerz, O. Lux, L. Magnusson, B. Mayer, M. Mech, R. Moore, J. Pelon, J. Quinting, S. Rahm, M. Rapp, M. Rautenhaus, O. Reitebuch, C.A. Reynolds, H. Sodemann, T. Spengler, G. Vaughan, M. Wendisch, M. Wirth, B. Witschas, K. Wolf, and T. Zinner, 2018: The North Atlantic Waveguide and Downstream Impact Experiment. Bull. Amer. Meteor. Soc., 99, 1607–1637, https://doi.org/10.1175/BAMS-D-17-0003.1

• Schnitt, S., E. Orlandi, M. Mech, A. Ehrlich, and S. Crewell: Characterisation of Water Vapor and Clouds during the Next-Generation Aircraft Remote-sensing for Validation (NARVAL)-South studies, IEEE Journal on Selected Topics in Earth Observation and Remote Sensing (JSTARS), doi:10.1109/JSTARS.2017.2687943.

• Stevens, B., F. Ament, S. Bony, S.Crewell, F. Ewald, S. Gross, A. Hansen, L. Hirsch, M. Jacob, T. Kölling, H. Konow, B. Mayer, M. wendisch, M. Wirth, K. wolf, S. Bakan, M. Bauer-Pfundstein, M. Brueck, J. Delanoe, A. Ehrlich, D. Farrell, M. Forde, F. Gödde, H. Grob, M. Hagen, E. Jäkel, F. Jansen, C. Klepp, M. Klingebiehl, M. Mech, G. Peters, M. Rapp, A. Wing, T. Zinner: A high-altitude long-range aircraft configured as a cloud observatory–the NARVAL expeditions, Bulletin of the American Meteorological Society,

• Wolf, K., Ehrlich, A., Jacob, M., Crewell, S., Wirth, M., and Wendisch, M.: Improvement of Airborne Retrievals of Cloud Droplet Number Concentration of Trade Wind Cumulus Using a Synergetic Approach, Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2018-266, in review, 2018.

• Jacob, M.,P. Kollias, M. Mech, S. Groß, M. Gutleben, M. Wirth, and S. Crewell: Investigating tropical clouds from shallow cumulus to strongly showering with synergistic airborne measurements, Vancouver, Canada, 9-13 July 2018, 15th joint Atmospheric Radiation/Cloud Physics conference AMS 2018, Abstract

• Jacob, M., S. Fox, S. Crewell, Comparing FAAM BAE 146 & HALO microwave radiometers, HALO Topical Workshop: 14 October 2016, Hamburg, 16 - 17 November, 2017.

• Jacob, M., S. Crewell, A. Ehrlich, H. Konow, M. Mech, E. Orlandi, S. Schnitt, K. Wolf: Comparative Characterisation of Maritime Clouds between Dry and Wet Season Over the Tropical North Atlantic by Airborne Observations, Radiation & Climate Gordon Research Conference, Lewiston, USA, 15 – 21 July 2017 Poster

• Crewell, S., M. Jacob, M. Mech, S. Bony, B. Stevens, M. Wendisch: Planned HALO/HAMP campaigns + Polar 5/MiRAC, ISMAR Workshop, Eumetsat, Darmstadt, 10 May, 2017.

• Jacob, M., B. Stevens, L. Hirsch, A. Schäfler S. Crewell, NARVAL and NAWDEX Teams: Recent HAMP activities, ISMAR Workshop, Eumetsat, Darmstadt, 10 May, 2017.

• Jacob, M., F. Ament , S. Crewell, A. Ehrlich, K. Wolf, M. Mech, E. Orlandi and S. Schnitt: Comparative Characterisation of Maritime Clouds between Dry and Wet Season Over the Tropical North Atlantic by Airborne Observations, EGU GA 2017, Vienna Austria, 24 April, 2017, Abstract.

• Jacob, M.: Study of maritime convection using the HALO Microwave Package (HAMP), GSGS Research Conference 4, Cologne, Germany, 2017-01-20 poster

• Schnitt, S., M. Mech, E. Orlandi, S. Crewell, HAMP – NARVAL Analysis, ISMAR/HALO Workshop, Hamburg, 7/8 June 2016.

• Orlandi E, E. V. Holm, M. Mech, S. Crewell, Influence of ECMWF background error covariances on the retrieval of temperature and humidity by the HAMP radiometer, Microwave Radiometry and Remote Sensing of the Environment (MICRORAD) conference, Pasadena, CA, USA, 24-27.03.2014.

• Orlandi E, M. Mech, S. Crewell, F. Ament, C. Klepp, Sensor synergy to detect clouds and precipitation: results of the first HALO-HAMP flight campaign, Microwave Radiometry and Remote Sensing of the Environment (MICRORAD) conference, Pasadena, CA, USA, 24-27.03.2014.

• Orlandi, E., M. Mech, S. Crewell, A. Lammert, Active and passive microwave retrieval algorithm for hydrometeor concentration profiles: application to the HAMP instrument, AGU fall meeting, San Francisco, US, 3-7.12.2012.

• Orlandi, E., M. Mech, S. Crewell, A. Lammert, A. Seifert and L. Hirsch, Retrieval development and test for HAMP, the HALO microwave package, Microwave Radiometry and Remote Sensing of the Environment (MICRORAD) conference, Tor Vergata, Italy, 5.-9.03.2012.

• Mech, M., S. Crewell, U. Löhnert, and E. Orlandi, Retrieval of temperature, humidity, and integrated hydrometeor contents from observations with the microwave package HAMP on the High Altitude and LOng range aircraft HALO, EUMETSAT Meteorological Satellite Conference 2011, Oslo, Norway, 5.-9.9.2011.

• Mech, M., G. Peters, L. Hirsch, and S. Crewell, HAMP - The Microwave Package on the „High Altitude and LOng range“ research aircraft HALO, 3rd International Workshop on Satellite-based Snowfall Measurements (IWSSM), Grainau, Germany, 30.3.-2.4.2011.

• Mech, M., S. Crewell, G. Peters, and L. Hirsch, HAMP - Erste Retrievalstudien für das Mikrowellen-Paket auf HALO, DACH Meteorologentagung 2010, Bonn, Germany, 20.-24.9.2010.

• Konow, H., Jacob, M., Ament, F., Crewell, S., Ewald, F., Hagen, M., Hirsch, L., Jansen, F., Mech, M., and Stevens, B., 2018: HALO Microwave Package measurements during Next-generation Remote sensing for VALidation Studies - North (NARVAL-North). World Data Center for Climate (WDCC) at DKRZ. https://doi.org/10.1594/WDCC/HALO_measurements_1

• Konow, H., Jacob, M., Ament, F., Crewell, S., Ewald, F., Hagen, M., Hirsch, L., Jansen, F., Mech, M., and Stevens, B., 2018: HALO Microwave Package measurements during Next-generation Remote sensing for VALidation Studies - South (NARVAL-South), https://doi.org/10.1594/WDCC/HALO_measurements_2

• Konow, H., Jacob, M., Ament, F., Crewell, S., Ewald, F., Hagen, M., Hirsch, L., Jansen, F., Mech, M., and Stevens, B., 2018: HALO Microwave Package measurements during Next-generation Remote sensing for VALidation Studies 2 (NARVAL2), https://doi.org/10.1594/WDCC/HALO_measurements_3

• Konow, H., Jacob, M., Ament, F., Crewell, S., Ewald, F., Hagen, M., Hirsch, L., Jansen, F., Mech, M., and Stevens, B., 2018: HALO Microwave Package measurements during North Atlantic Waveguide and Downstream impact EXperiment (NAWDEX). World Data Center for Climate (WDCC) at DKRZ. https://doi.org/10.1594/WDCC/HALO_measurements_4