Observations of Temperature in the Upper Troposphere and Lower Stratosphere of Tropical Weather Disturbances

Davis, Christopher A.; Ahijevych, David; Haggerty, Julie; Mahoney, Michael J.

doi:10.1175/jas-d-13-0278.1

Cited by 20 publications

(22 citation statements)

References 47 publications

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“…Multiple tropopause structures are clearly visible in the profiles that occurred within 100 km from the TC, though the number of profiles available is small. These multiple tropopauses are similar to double tropopauses observed by Corti et al (2008), Biondi et al (2011), andDavis et al (2014). The cause for these multiple tropopauses might be either due to clouds (Biondi et al, 2013), wave activity, cirrus deck or ozone (Mehta et al, 2011), which demands separate investigation.…”

Section: Vertical Thermal Structure Of Utls Within 500 Km From the Tcsupporting

confidence: 59%

“…Studies include the thermal and dynamical structure of UTLS during TC (Koteswaram, 1967), horizontal and vertical structure of temperature in the cyclone (Waco, 1970), temperature and ozone variations in a hurricane (Penn, 1965), troposphere-stratosphere transport and dehydration in cyclones (Danielsen, 1993), UTLS structure during TCs using AIRS and MLS measurements (Ray and Rosenlof, 2007), RO bending angle anomalies during tropical cyclones (Biondi et al, 2011), thermal structure of intense convective clouds derived from GPS RO (Biondi et al, 2012), estimating the TC cloud top height and vertical temperature structure using GPS RO measurements (Biondi et al, 2013), and observations of temperature in the UTLS of tropical weather disturbances (Davis et al, 2014). Note that the above list is only indicative, not exhaustive.…”

Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

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Effect of tropical cyclones on the tropical tropopause parameters observed using COSMIC GPS RO data

Babu

Ratnam

Basha³

et al. 2015

Atmos. Chem. Phys.

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Abstract. Tropical cyclones (TCs) are deep convective synoptic-scale systems that play an important role in modifying the thermal structure, tropical tropopause parameters and hence also modify stratosphere-troposphere exchange (STE) processes. In the present study, high vertical resolution and high accuracy measurements from COSMIC Global Positioning System (GPS) radio occultation (RO) measurements are used to investigate and quantify the effect of tropical cyclones that occurred over Bay of Bengal and Arabian Sea in the last decade on the tropical tropopause parameters. The tropopause parameters include cold-point tropopause altitude (CPH) and temperature (CPT), lapse-rate tropopause altitude (LRH) and temperature (LRT) and the thickness of the tropical tropopause layer (TTL), that is defined as the layer between convective outflow level (COH) and CPH, obtained from GPS RO data. From all the TC events, we generate the mean cyclone-centred composite structure for the tropopause parameters and removed it from the climatological mean obtained from averaging the GPS RO data from 2002 to 2013. Since the TCs include eye, eye walls and deep convective bands, we obtained the tropopause parameters based on radial distance from the cyclone eye. In general, decrease in the CPH in the eye is noticed as expected. However, as the distance from the cyclone eye increases by 300, 400, and 500 km, an enhancement in CPH (CPT) and LRH (LRT) is observed. Lowering of CPH (0.6 km) and LRH (0.4 km) values with coldest CPT and LRT (2-3 K) within a 500 km radius of the TC centre is noticed. Higher (2 km) COH leading to the lowering of TTL thickness (2-3 km) is clearly observed. There are multiple tropopause structures in the profiles of temperature obtained within 100 km from the centre of the TC. These changes in the tropopause parameters are expected to influence the water vapour transport from the troposphere to the lower stratosphere, and ozone from the lower stratosphere to the upper troposphere, hence influencing STE processes.

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Section: Vertical Thermal Structure Of Utls Within 500 Km From the Tcsupporting

confidence: 59%

Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

Effect of tropical cyclones on the tropical tropopause parameters observed using COSMIC GPS RO data

Babu

Ratnam

Basha³

et al. 2015

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…The daily mean temperature increased near the storm by about 3 K at 9 km altitude for pre‐Karl flights over 10–14 September [ Smith and Montgomery , ]. The observed warm core is consistent with previous studies of tropical cyclones [ Biondi et al ., ; Davis et al ., ; Houze et al ., ; Kidder et al ., ; Merrill , ]. The mean system relative humidity remained relatively constant below about 3 km over 10–14 September, while humidity generally increased in the midlevel to 10 km [ Smith and Montgomery , ].…”

Section: Resultsmentioning

confidence: 98%

Airborne GPS radio occultation refractivity profiles observed in tropical storm environments

et al. 2015

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Airborne GPS radio occultation (ARO) data have been collected during the 2010 PRE-Depression Investigation of Cloud systems in the Tropics (PREDICT) experiment. GPS signals received by the airborne Global Navigation Satellite System Instrument System for Multistatic and Occultation Sensing (GISMOS) are used to retrieve vertical profiles of refractivity in the neutral atmosphere. The system includes a conventional geodetic GPS receiver component for straightforward validation of the analysis method in the middle to upper troposphere, and a high-sample rate (10 MHz) GPS recorder for postprocessing complex signals that probe the lower troposphere. The results from the geodetic receivers are presented here. The retrieved ARO profiles consistently agree within~2% of refractivity profiles calculated from the European Center for Medium-Range Weather Forecasting model Interim reanalyses as well as from nearby dropsondes and radiosondes. Changes in refractivity obtained from ARO data over the 5 days leading to the genesis of tropical storm Karl are consistent with moistening in the vicinity of the storm center. An open-loop tracking method was implemented in a test case to analyze GPS signals from the GISMOS 10 MHz recording system for comparison with geodetic receiver data. The open-loop mode successfully tracked~2 km deeper into the troposphere than the conventional receiver and can also track rising occultations, illustrating the benefit from the high-rate recording system. Accurate refractivity retrievals are an important first step toward the future goal of assimilating moisture profiles to improve forecasting of developing storms using this new GPS occultation technique.

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“…Another feature characteristic of storms is the double tropopause (Danielsen, 1993;Corti et al, 2008;Biondi et Davis et al, 2014), which is visible in Fig. 6b for TC category 5 (dotted lines).…”

Section: Thermal Structurementioning

confidence: 93%

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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Observations of Temperature in the Upper Troposphere and Lower Stratosphere of Tropical Weather Disturbances

Cited by 20 publications

References 47 publications

Effect of tropical cyclones on the tropical tropopause parameters observed using COSMIC GPS RO data

Effect of tropical cyclones on the tropical tropopause parameters observed using COSMIC GPS RO data

Airborne GPS radio occultation refractivity profiles observed in tropical storm environments

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

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