Finished projects
A detailed model of the ascent of sounding balloons through the troposphere into the lower stratosphere accounts for both variation of the drag coefficient with altitude and the heat transfer in the balloon filling gas with its induced transient imbalance of buoyance. As parameterization of the drag coefficient dependence on the Reynolds number in the relevant regime is lacking, a reference relation is derived based on the flight dataset collected during the Lindenberg Upper Air Methods Intercomparison (LUAMI). The balloon internal heat transfer is solved applying the Finite Element Method. In conjunction with GPS data from the sounding, the model can be used to derive small scale vertical wind fluctuations with an uncertainty of 0.5 ms-1 in the troposphere and 0.2 ms-1 in the stratosphere (external pageGallice et al., 2011call_made).
In a case study, COBALD and CFH data obtained during the LUAMI campaign was analyzed with a detailed microphysical model driven by LAGRANTO air parcel trajectories based on COSMO-7 wind fields. The observed ice nucleation could be explained by the conventional cloud microphysics when small-scale temperature fluctuations not resolved in the trajectories are taken into account (external pageBrabeck et al., 2012call_made).
The Arctic stratosphere was probed from with COBALD, CFH, and the FLASH-B Lyman-α hygrometer providing unparalleled evidence of dehydration: up to 1.6 ppmv in 20 – 24 km altitude, and rehydration by up to 0.9 ppmv in a one km thick layer below, caused by gravitational settling of ice particles (external pageKhaykin et al., 2013call_made). This was reproduced by the Zurich Optical and Microphysical box Model (ZOMM), extended to account for sedimentation in vertical columns, and applying a newly developed nucleation parameterization for NAT (nitric acid trihydrate) and ice (external pageEngel et al., 2014call_made).
In tropical regions, too, the TRO-Pico campaign carried out from Bauru, Brazil, in March 2012 gathered balloon profiles for water vapor and optical backscatter. Analysis of this data suggest cross-tropopause transport of water vapor. This moistening of the tropical tropopause layer (TTL) was supported by satellite observations in combination with trajectory and transport modelling (external pageKhaykin et al., 2016call_made).
Microphysical process in cirrus clouds reached a new level of understanding by introducing the cirrus match technique: Combined prediction of balloon ascent tracks and connecting air parcels permits the coordination of two balloon launches in space and time, such that the same air parcel is probed twice by the water vapor and optical backscatter payload. Simulating the match in model analysis, these data constrain key microphysical parameters of the ZOMM model, such as the fraction of heterogeneous versus homogeneous nucleation and the water accommodation on the nucleated ice crystals, along with the temperature fluctuations along the air parcels (external pageCirisan et al., 2014call_made).
The volcanic plume from the eruption of Mount Kelud on 13 February 2014 was observed during 14 and 24 May 2014 by five COBALD sondes launched from Darwin, Australia, and a further heavy payload from Coroborree on 20 May 2014. In conjunction with satellite based lidar measurements by CALIOP on CALIPSO the in-situ observations suggest that fine ash particles represent 20 to 28% of the cloud observed three month after the eruption, with a separation of 1.5 to 2 km between the sulfate and ash layers. The upward Brewer-Dobson circulation reduces the ash particle sedimentation, doubling its lifetime and yielding an estimated total radiative forcing of the Kelud plume of -0.08 W/m2, approximately one fourth of which is attributed to the fine ash and its long atmospheric lifetime (external pageVernier et al., 2016call_made).
COBALD observations of an enhanced aerosol layer in the Asian summer monsoon anticyclone started in 2010. Detailed analysis of the summer 2013 data from Lhasa, Tibet, supported by that from CALIOP on CALIPSO and trajectory analysis of the pollution transport in the UT/LS suggests that Asian Tropopause Aerosol Layer (ATAL) arises from secondary aerosol formation and growth in the cold and moist monsoon environment. The ATAL short term regional radiative forcing is estimated -0.1 W/m2 (external pageVernier et al. 2015call_made). An overview of the Balloon measurements in ATAL (BATAL) from India and Saudi Arabia between 2014 and 2017 is provided the overview of external pageVernier et al., 2018call_made.
References
A. Gallice, F. G. Wienhold; C. R. Hoyle, F. Immler, and T,Peter (2011). Modeling the ascent of sounding balloons: derivation of the vertical air motion. Atmos. Meas. Tech., 4, 2235-2253, doi: 10.5194/amt-4-2235-2011.
M. Brabec, F. G. Wienhold, B. P. Luo, H. Vömel, F. Immler, P. Steiner, E. Hausammann, U. Weers, and T. Peter (2012). Particle backscatter and relative humidity measured across cirrus clouds and comparison with microphysical cirrus modeling. Atmos. Chem. Phys., 12, 9135-9148, doi:10.5194/acp-12-9135-2012.
S. M. Khaykin, I. Engel, H. Vömel, I. M. Formanyuk, R. Kivi, L. I. Korshunov, M. Krämer, A. D. Lykov, S. Meier, T. Naebert, M. C. Pitts, M. L. Santee, N. Spelten, F. G. Wienhold, V. A. Yushkov, and T. Peter (2013). Arctic stratospheric dehydration – Part 1: Unprecedented observation of vertical redistribution of water. Atmos. Chem. Phys., 13, 11503–11517, doi:10.5194/acp-13-11503-2013
I. Engel, B. P. Luo, S. M. Khaykin, F. G. Wienhold, H. Vömel, R. Kivi, C. R. Hoyle, J.-U. Grooß, M. C. Pitts, and T. Peter (2014). Arctic stratospheric dehydration – Part 2: Microphysical modeling. Atmos. Chem. Phys., 14, 3231–3246, doi:10.5194/acp-14-3231-2014
A. Cirisan, B. P. Luo, I. Engel, F. G. Wienhold, U. K. Krieger, U. Weers, G. Romanens, G. Levrat, P. Jeannet, D. Ruffieux, R. Philipona, B. Calpini, P. Spichtinger, and T. Peter (2014). Balloon-borne match measurements of mid-latitude cirrus clouds. Atmos. Chem. Phys., 14, 7341–7365, doi:10.5194/acp-14-7341-2014.
D. W. Fahey, R.-S. Gao, O. Möhler, H. Saathoff, C. Schiller, V. Ebert, M. Krämer, T. Peter, N. Amarouche, L. M. Avallone, R. Bauer, Z. Bozóki, L. E. Christensen, S. M. Davis, G. Durry, C. Dyroff, R. L. Herman, S. Hunsmann, S. M. Khaykin, P. Mackrodt, J. Meyer, J. B. Smith, N. Spelten, R. F. Troy, H. Vömel, S. Wagner, and F. G. Wienhold (2014). The AquaVIT-1 intercomparison of atmospheric water vapor measurement techniques. Atmos. Meas. Tech., 7, 3177-3213, DOI: 10.5194/amtd-7-3177-2014.
J.-P. Vernier, T. D. Fairlie, M. Natarajan, F. G. Wienhold, J. Bian, B. G. Martinsson, S. Crumeyrolle, L. W. Thomason, and K. M. Bedka (2015). Increase in upper tropospheric and lower stratospheric aerosol levels and its potential connection with Asian pollution. J. Geophys. Res. Atmos., 120, doi:10.1002/ 2014JD022372.
S. M. Khaykin, J.-P. Pommereau, E. D. Riviere, G. Held, F. Ploeger, M. Ghysels, N. Amarouche, J.-P. Vernier, F. G. Wienhold, and D. Ionov (2016). Evidence of horizontal and vertical transport of water in the Southern Hemisphere tropical tropopause layer (TTL) from high-resolution balloon observations. Atmos. Chem. Phys., 16, 12273–12286, doi:10.5194/acp-16-12273-2016.
J.-P. Vernier, T. D. Fairlie, T. Deshler, M. Natarajan, T. Knepp, K. Foster, F. G. Wienhold, K. M. Bedka, L. Thomason, and C. Trepte (2016). In situ and space-based observations of the Kelud volcanic plume: The persistence of ash in the lower stratosphere. J. Geophys. Res. Atmos., 121, doi:10.1002/2016JD025344.
J.-P. Vernier, T. D. Fairlie, T. Deshler, M. Venkat Ratnam, H. Gadhavi, B. S. Kumar, M. Natarajan, A. K. Pandit, S. T. Akhil Raj, A. Hemanth Kumar, A. Jayaraman, A. K. Singh, N. Rastogi, P. R. Sinha, S. Kumar, S. Tiwari, T. Wegner, N. Baker, D. Vignelles, G. Stenchikov, I. Shevchenko, J. Smith, K. Bedka, A. Kesarkar, V. Singh, J. Bhate, V. Ravikiran, M. Durga Rao, S. Ravindrababu, A. Patel, H. Vernier, F. G. Wienhold, H. Liu, T. N. Knepp, L. Thomason, J. Crawford, L. Ziemba, J. Moore, S. Crumeyrolle, M. Williamson, G. Berthet, F. Jégou, and J.-B. Renard (2018). BATAL: The Balloon Measurement Campaigns of the Asian Tropopause Aerosol Layer, Bull. Amer. Meteor. Soc, 99 (5), 955–973, doi:10.1175/BAMS-D-17-0014.1.
S. Brunamonti, T. Jorge, P. Oelsner, S. Hanumanthu, B. Singh, K. R. Kumar, S. Sonbawne, S. Meier, D. Singh, F. G. Wienhold, B. P. Luo, M. Boettcher, Y. Poltera, H. Jauhiainen, R. Kayastha, J. Karmacharya, R. Dirksen, M. Naja, M. Rex, S. Fadnavis, and T. Peter (2018). Balloon-borne measurements of temperature, water vapor, ozone and aerosol backscatter on the southern slopes of the Himalayas during StratoClim 2016–2017. Atmos. Chem. Phys., 18, 15937–15957, doi: 10.5194/acp-18-15937-2018.
Q. He, J. Ma, X. Zheng, X. Yan, H. Vömel, F. G. Wienhold, W. Gao, D. Liu, G. Shi, and T. Cheng (2019). Observational evidence of particle hygroscopic growth in the upper troposphere–lower stratosphere (UTLS) over the Tibetan Plateau. Atmos. Chem. Phys., 19, 8399–8406, doi: 10.5194/acp-19-8399-2019.
S. Brunamonti , L. Füzér, T. Jorge, Y. Poltera, P. Oelsner , S. Meier, R. Dirksen, M. Naja, S. Fadnavis , J. Karmacharya , F. G. Wienhold , B. P. Luo, H. Wernli , and T. Peter (2019). Water Vapor in the Asian Summer Monsoon Anticyclone: Comparison of Balloon‐Borne Measurements and ECMWF Data.
Journal of Geophysical Research: Atmospheres, 124. doi: 10.1029/2018JD030000.