GPS Radio Occultation for studying extreme events Riccardo Biondi (1), A. K. Steiner (1), T. Rieckh (1) and G. Kirchengast (1,2) (1) Wegener Center for Climate and Global Change, University of Graz, Austria (2) Institute for Geophysics, Astrophysics, and Meteorology/Institute of Physics (IGAM/IP), University of Graz, Austria Eighth FORMOSAT-3/COSMIC Data Users' Workshop @ Boulder - CO, USA, 1 October 2014
20 15 10 5 0-8 -6-4 -2 0 2 4 6 8 Temperature anomaly [K] Outline GPS radio occultation for studying extreme events GPS RO archive and climatology Background Overshooting detection Volcanic cloud challenges Volcanic cloud - State of the art Altitude above msl [km] Volcanic cloud - Case study Conclusions
GPS radio occultation the datasets # occultations Year
GPS RO coverage Full archive RO distribution [#] January RO distribution July RO distribution [#]
Background Past results Biondi et al., Thermal structure of intense convective clouds derived from GPS radio occultations, Atmos. Chem. Phys., 12, 2012. Biondi et al., Tropical cyclone cloud-top height and vertical temperature structure detection using GPS radio occultation measurements, J. Geophys. Res., 118, 2013.
TC-RO co-location archive Co-location of Tropical cyclones best tracks and GPS RO Time window: 6 hours Spatial window: 600 km Period: 2001 2012 Number of selected cases: 20732 479 ROs co-located within 10 minutes from the TC track 503 ROs co-located within 100 km from the TC center (47 within 30 km) 16 TC monitored with more than 90 ROs RO selection per basin and TC intensity Sub-selection of tropical and extra-tropical occultations Co-location of tropical cyclones, GPS RO and CALIOP Number of selected cases: > 1000 (!!) Biondi, R., Steiner, A. K., Kirchengast, G. And Rieckh, T.,: A characterization of thermal structure and conditions for overshooting of tropical and extratropical cyclones with GPS radio occultation, Atmos. Chem. Phys. Discuss., 2014.
Overshooting detection H coldest_std > H mm_trop + H mstd_trop H coldest_std+1 > H mm_trop + H mstd_trop + 0.996 km Rieckh et al., Characteristics of tropopause parameters as observed with GPS radio occultation, Atmos. Tech. Meas. Discuss., 2014.
Overshooting map * H coldest_std > H mm_trop + H mstd_trop * H coldest_std+1 > H mm_trop + H mstd_trop + 0.996 km
Overshooting map validation Romps and Kuang, Overshooting convection in tropical cyclones, Geophys. Res. Lett., 2009.
Volcanic cloud challenges Main challenges of volcanic ash cloud detection/monitoring (Tupper et al., Remote Sens. Environ., 2004 Prata, Nat. Hazards, 2009 ESA-EUMETSAT workshop, 2010 Stohl et al., Atmos. Chem. Phys., 2011) Cloud top height determination Impact on the radiative budget Discrimination from other type of clouds Density determination Cloud extent
Background Wang et al., Immediate impact of the Mt Chaiten eruption on atmosphere from FORMOSAT-3/COSMIC constellation, Geophys. Res. Lett., 2009.
Background Okazaki and Heki, Atmospheric temperature changes by volcanic eruptions: GPS radio occultation observations in the 2010 Icelandic and 2011 Chilean cases, J. Volcanol. Geoph. Res., 2012. Eighth FORMOSAT-3/COSMIC Data Users' Workshop @ Boulder - CO, USA, 1 October 2014
Science discussion Bourassa et al., Large volcanic aerosol load in the stratosphere linked to asian monsoon transport, Science, 2012.? Fromm et al., Comment on «Large volcanic aerosol load in the stratosphere linked to asian monsoon transport», Science, 2013. Bourassa et al., Response to Comment on «Large volcanic aerosol load in the stratosphere linked to asian monsoon transport», Science, 2013. Bourassa et al. Report on the 13 June 2011 eruption of the Nabro volcano and satellite observations of stratospheric aerosol that they attribute to troposphere to stratosphere ascent via the Asian monsoon. They claim that the 13 June top injection height was well below the tropopause. We will show that the 13 June Nabro eruption plume was clearly stratospheric... Fromm et al., evaluated the cloud top altitude using CO 2 slicing technique (MODIS data), no tropopause evaluation Bourassa reports ash clouds altitudes of 9.1 to 13.7 km (citing Global Volcanism Program, Smithsonian Institution) and tropopause altitude at 18.1 km from Saudi Arabia radiosonde on 12 and 13 June. Did the volcanic ash cloud reach the stratosphere? Where the tropopause actually was? Did the volcanic ash cloud reach the stratosphere directly or driven by convective systems?
Case study Nabro 2011 & Puyehue 2011 Mainly SO 2 eruption GPS RO - OMI 214 cases no CALISPO availability during the eruption Mainly ash eruption GPS RO AIRS/IASI 1022 cases CALIPSO available for some days
Case study Nabro 2011 (SO 2 eruption) 30 N 60 E 15 N 15 N 0 20 8.66 km 7.1 km 6.27 km 15 Altitude above msl [km] 10 5 Altitude above msl [km] 20 15 10 5 1-11June 38 cases 0-8 -6-4 -2 0 2 4 6 8 Temperature anomaly [K] 12-15 June 14 cases 0-8 -6-4 -2 0 2 4 6 8 Temperature anomaly [K]
Case study Nabro 2011 (SO 2 eruption) Nabro May 2011 Nabro July 2011 20 20 15 15 10 10 5 May 5 July 0-10 -5 0 5 10 0-10 -5 0 5 10 20 20 Altitude above msl [km] 15 10 Altitude above msl [km] 15 10 5 1-11June 38 cases 0-8 -6-4 -2 0 2 4 6 8 Temperature anomaly [K] 12 June 5 12-15 June 14 cases 0-8 -6-4 -2 0 2 4 6 8 Temperature anomaly [K]
Case study Puyehue 2011 (ash eruption) AIRS/IASI ash detection 5th of June 2014, the day after the eruption CALIOP backscater 25 20 Altitude above msl [km] 15 10 10.9 5 0-15 -10-5 0 5 10 Temperature anomaly [K] RO profiles into the ash cloud Eighth FORMOSAT-3/COSMIC Data Users' Workshop @ Boulder - CO, USA, 1 October 2014
Conclusions TCs conclusions Biondi, R., Steiner, A. K., Kirchengast, G. And Rieckh, T.,: A characterization of thermal structure and conditions for overshooting of tropical and extratropical cyclones with GPS radio occultation, Atmos. Chem. Phys. Discuss., 2014. Volcanic cloud conclusions Impact on the radiative budget There is no better way than GPS ROs for determining the tropopause altitude with global coverage and high vertical resolution Cloud top height determination We can definitely contribute, especially once the dataset of GPS RO co-located with CALIOP and AIRS/IASI will be ready Discrimination from other type of clouds It is definitely feasible deepening the connection between temperature anomaly inversion and cloud top altitude. The use of bending angle profile (much more sensitive than temperature) could improve the analyses Cloud extent I depends on the future GNSS RO coverage and temporal resolution...
The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007-2013) under REA grant agreement n 328233. Eighth FORMOSAT-3/COSMIC Data Users' Workshop @ Boulder - CO, USA, 1 October 2014