Collaborations

CONSYDER will be supervised by Wegener Center (University of Graz - Austria).

The background was developed at DTU-Space (DK) in collaboration with DMI (DK)

Collaborations are already ongoing with:
- UCAR/COSMIC (USA)
- NCAR/ACP (USA)
- ISAC/CNR (IT)

Connected projects

Convective Radio Occultations Campaign (CROC)

CROC is a campaign run within the US Atmospheric Radiation Measurement (ARM) Climate Research Facility, here the details: http://www.arm.gov/campaigns/twp2012CROC

Background

Thermal structure of intense convective clouds derived from GPS radio occultations, Biondi, R., Randel, W., Ho, S.-P., Neubert, T. and Syndergaard, S., Atmos. Chem. Phys., 12, 5309–5318, 2012, doi:10.5194/acp-12-5309-2012

www.atmos-chem-phys.net/12/5309/2012/

Thermal structure associated with deep convective clouds is investigated using Global Positioning System (GPS) radio occultation measurements. GPS data are insensitive to the presence of clouds, and provide high vertical resolution and high accuracy measurements to identify associated temperature behavior. Deep convective systems are identified using International Satellite Cloud Climatology Project (ISCCP) satellite data, and cloud tops are accurately measured using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO) lidar observations; we focus on 53 cases of near-coincident GPS occultations with CALIPSO profiles over deep convection. Results show a sharp spike in GPS bending angle highly correlated to the top of the clouds, corresponding to anomalously cold temperatures within the clouds. Above the clouds the temperatures return to background conditions, and there is a strong inversion at cloud top. For cloud tops below 14 km, the temperature lapse rate within the cloud often approaches a moist adiabat, consistent with rapid undiluted ascent within the convective systems.

Background 

Radio occultation bending angle anomalies during tropical cyclones, Biondi, R., Neubert, T., Syndergaard, S. and Nielsen, J., Atmos. Meas. Tech. Discuss., 4, 1371–1395, 2011, doi:10.5194/amtd-4-1371-2011 

www.atmos-meas-tech-discuss.net/4/1371/2011/

The tropical deep convection affects the radiation balance of the atmosphere changing the water vapor mixing ratio and the temperature of the upper troposphere lower stratosphere. The aim of this work is to better understand these processes and to investigate if severe storms leave a significant signature in radio occultation profiles in the tropical tropopause layer. Using tropical cyclone best track database and data from different GPS radio occultation missions (COSMIC, GRACE, CHAMP, SACC and GPSMET), we selected 1194 profiles in a time window of 3 h and a space window of 300 km from the eye of the cyclone. We show that the bending angle anomaly of a GPS radio occultation signal is typically larger than the climatology in the upper troposphere and lower stratosphere and that a double tropopause during deep convection can easily be
detected using this technique. Comparisons with co-located radiosondes, climatology of tropopause altitudes and GOES analyses are also shown to support the hypothesis that the bending angle anomaly can be used as an indicator of convective towers. The results are discussed in connection to the GPS radio occultation receiver which will be part of the Atomic Clock Ensemble in Space (ACES) payload on the International Space Station.

Background

Measurements of the upper troposphere and lower stratosphere during tropical cyclones using the GPS radio occultation technique, Biondi, R., Neubert, T., Syndergaard, S. and Nielsen, J., Advance in Space Research, Vol. 47 (2), pp. 348-355, 2011. 

http://www.sciencedirect.com/science/article/pii/S0273117710003765

Water vapour transport to the upper troposphere and lower stratosphere by deep convective storms affects the radiation balance of the atmosphere and has been proposed as an important component of climate change. The aim of the work presented here is to understand if the GPS radio occultation technique is useful for characterization of this process. Our assessment addresses the question if severe storms leave a significant signature in radio occultation profiles in the upper troposphere/lower stratosphere. Radio occultation data from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) were analyzed, focusing on two particular tropical cyclones with completely different characteristics, the hurricane Bertha, which formed in the Atlantic Basin during July 2008 and reached a maximum intensity of Category 3, and the typhoon Hondo, which formed in the south Indian Ocean during 2008 reaching a maximum intensity of Category 4. The result is positive, suggesting that the bending angle of a GPS radio occultation signal contains interesting information on the atmosphere around the tropopause, but not any information regarding the water vapour. The maximum percentage anomaly of bending angle between 14 and 18 km of altitude during tropical cyclones is typically larger than the annual mean by 5–15% and it can reach 20% for extreme cases. The results are discussed in connection to the GPS radio occultation receiver which will be part of the Atomic Clock Ensemble in Space (ACES) payload on the International Space Station.

The project

The deep convective systems play a fundamental role in atmospheric circulation and climate. Thunderstorms and mesoscale convective systems produce fast vertical transport, redistributing water vapor and trace gases and influencing the thermal structure of the Upper Troposphere-Lower Stratosphere (UTLS). These processes influence the climate and create damages and lives loss. The determination of cloud top height and the thermal structure of the system are important for the understanding of the climate effect and to detect and forecast the strength of the storm.
The ongoing satellite missions do not provide suitable time/space coverage to study such kind of phenomena with adequate horizontal and vertical resolution and sensitivity. The ground based measurements and campaigns are too sparse ...and the acquisitions at the UTLS altitudes are always difficult and sometimes not reliable.
The Global Positioning System (GPS) Radio Occultation (RO) technique enables measurement of atmospheric density structure in any meteorological condition, with extremely high accuracy, precision and vertical resolution, providing a global coverage of the Earth. The objective of the proposal is to combine the capabilities of the GPS RO technique with the high temporal resolution of ground based instruments, with the spatial resolution of other satellite instruments and with the accuracy and precision of campaigns measurements, to define a solid algorithm
detecting the storm cloud top with high accuracy using the RO profiles. This will allow to get a good understanding of the role of convection in determining the thermal structure and composition of the UTLS both in the tropics and in the extra-tropics, and to improve the forecast of the intensity of severe events. The analysis of the temporal and zonal variation of the GPS signal will also be used to analyze the climate changes and the contribution of the convection to the climate changes.