Characteristics of tropopause parameters as observed with  GPS  radio occultation

Rieckh, Therese; Scherllin‐Pirscher, Barbara; Ladstädter, Florian; Foelsche, Ulrich

doi:10.5194/amt-7-3947-2014

Cited by 55 publications

(53 citation statements)

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“…4 and top layer in Fig. 5 (100 to 300 hPa or approximately 9 to 17 km) represent upper tropospheric, tropopause region, and lower stratospheric pressure levels, depending on latitude and time of the year (Rieckh et al, 2014). These layers are as well part of the range of highest GPSRO data quality.…”

Section: Global Annual Mean Differences Within Pressure Layersmentioning

confidence: 99%

Climate intercomparison of GPS radio occultation, RS90/92 radiosondes and GRUAN from 2002 to 2013

et al. 2015

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Abstract.Observations from the GPS radio occultation (GP-SRO) satellite technique and from the newly established GCOS Reference Upper Air Network (GRUAN) are both candidates to serve as reference observations in the Global Climate Observing System (GCOS). Such reference observations are key to decrease existing uncertainties in upperair climate research. There are now more than 12 years of data available from GPSRO, with the recognized properties high accuracy, global coverage, high vertical resolution, and long-term stability. These properties make GPSRO a suitable choice for comparison studies with other upper-air observational systems. The GRUAN network consists of reference radiosonde ground stations (16 at present), which adhere to the GCOS climate monitoring principles. In this study, we intercompare GPSRO temperature and humidity profiles and Vaisala RS90/92 data from the "standard" global radiosonde network over the whole 2002 to 2013 time frame. Additionally, we include the first years of GRUAN data (using Vaisala RS92), available since 2009. GPSRO profiles which occur within 3 h and 300 km of radiosonde launches are used. Overall very good agreement is found between all three data sets with temperature differences usually less than 0.2 K. In the stratosphere above 30 hPa, temperature differences are larger but still within 0.5 K. Day/night comparisons with GRUAN data reveal small deviations likely related to a warm bias of the radiosonde data at high altitudes, but also residual errors from the GPSRO retrieval process might play a role. Vaisala RS90/92 specific humidity exhibits a dry bias of up to 40 % in the upper troposphere, with a smaller bias at lower altitudes within 15 %. GRUAN shows a marked improvement in the bias characteristics, with less than 5 % difference to GPSRO, up to 300 hPa. GPSRO dry temperature and physical temperature are validated using radiosonde data as reference. We find that GPSRO provides valuable long-term stable reference observations with well-defined error characteristics for climate applications and for anchoring other upperair measurements.

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Section: Global Annual Mean Differences Within Pressure Layersmentioning

confidence: 99%

Climate intercomparison of GPS radio occultation, RS90/92 radiosondes and GRUAN from 2002 to 2013

et al. 2015

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“…Including RO into reanalyses can reduce biases in the troposphere and stratosphere in both hemispheres (Poli et al, 2010). Several studies also used RO data to investigate dynamical features of the atmosphere such as waves (Randel and Wu, 2005;de la Torre and Alexander, 2005;Tsuda, 2014), the ENSO (ScherllinPirscher et al, 2012;Sun et al, 2014), tropopause characteristics (Schmidt et al, 2008;Rieckh et al, 2014;Peevey et al, 2014;Randel et al, 2003;Schmidt et al, 2005), and blocking .…”

Section: Radio Occultation Datamentioning

confidence: 99%

A global perspective on atmospheric blocking using GPS radio occultation – one decade of observations

Brunner

Steiner

2017

Atmos. Meas. Tech.

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Abstract. Atmospheric blocking represents a weather pattern where a stationary high-pressure system weakens or reverses the climatological westerly flow at mid-latitudes for up to several weeks. It is closely connected to strong anomalies in key atmospheric variables such as geopotential height, temperature, and humidity. Here we provide, for the first time, a comprehensive, global perspective on atmospheric blocking and related impacts by using an observation-based data set from Global Positioning System (GPS) radio occultation (RO) from 2006 to 2016. The main blocking regions in both hemispheres and seasonal variations are found to be represented well in RO data. The effect of blocking on vertically resolved temperature and humidity anomalies in the troposphere and lower stratosphere is investigated for blocking regions in the Northern and Southern hemispheres, respectively. We find a statistically significant correlation of blocking with positive temperature anomalies, exceeding 3 K in the troposphere, and a reversal above the tropopause with negative temperature anomalies below −3 K in the lower stratosphere. Specific humidity is positively correlated with temperature throughout the troposphere with larger anomalies revealed in the Southern Hemisphere. At the eastern and equatorward side of the investigated blocking regions, a band of tropospheric cold anomalies reveals advection of cold air by anticyclonic motion around blocking highs, which is less distinct in the Southern Hemisphere due to stronger zonal flow. We find GPS RO to be a promising new data set for blocking research that gives insight into the vertical atmospheric structure, especially in light of the expected increase in data coverage that future missions will provide.

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“…1 with about 60 000 cases in January 2007 (a) and in July 2007 (b): the tropopause has a seasonal variability with higher altitudes during the Northern Hemisphere winter (Rieckh et al, 2014).…”

Section: Tropopause Altitudesmentioning

confidence: 99%

“…Tropopause altitudes were computed from individual RO temperature profiles (Rieckh et al, 2014), using the lapse rate definition of the World Meteorological Organization (WMO, 1957). This definition allows for finding multiple tropopauses, which was a requirement for this study.…”

Section: Tropopause Altitudesmentioning

confidence: 99%

Characterization of thermal structure and conditions for overshooting of tropical and extratropical cyclones with GPS radio occultation

et al. 2015

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Abstract. The thermal structure of tropical cyclones (TCs) in different ocean basins is studied using global positioning system (GPS) radio occultation (RO) measurements co-located with TCs' best tracks. The objective of this work is to understand the mutual influence of TCs and atmospheric parameters in different regions. We selected more than 20 000 GPS RO profiles co-located with TCs in a time window of 6 h and space window of 600 km from the TC center in the period 2001-2012 and classified them by intensity of the cyclone and by ocean basin. The results show that TCs have different characteristics depending on the basin, which affects the cloud top altitude and the TC thermal structure which usually shows a negative temperature anomaly near the cloud top altitude. In the Northern Hemisphere ocean basins, the temperature anomaly becomes positive above the cloud top while in the Southern Hemisphere ocean basins it stays negative up to about 25 km in altitude.Furthermore, in the Southern Hemisphere the storms reach higher cloud top altitudes than in the Northern Hemisphere ocean basins, indicating that possible overshootings overpass the climatological tropopause more deeply at extratropical latitudes. The comparison of the TC thermal structure with the respective monthly mean tropopause altitude allows for a detailed analysis of the probability for possible overshooting. While the co-locations between GPS ROs and TC tracks are well distributed in all the ocean basins, conditions for possible overshootings are found to be more frequent in the Southern Hemisphere basins and in the northern Indian Ocean basin. However, the number of possible overshootings for high intensity storms (i.e., TC categories 1-5) is the highest in the western Pacific Ocean basin.

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Characteristics of tropopause parameters as observed with GPS radio occultation

Cited by 55 publications

References 50 publications

Climate intercomparison of GPS radio occultation, RS90/92 radiosondes and GRUAN from 2002 to 2013

Climate intercomparison of GPS radio occultation, RS90/92 radiosondes and GRUAN from 2002 to 2013

A global perspective on atmospheric blocking using GPS radio occultation – one decade of observations

Characterization of thermal structure and conditions for overshooting of tropical and extratropical cyclones with GPS radio occultation

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