Balloon-borne cryogenic frost-point hygrometer observations of water vapour in the tropical upper troposphere and lower stratosphere over India: First results

Sunilkumar, S. V.; Muhsin, M.; Ramkumar, Geetha; Rajeev, K.; Sijikumar, S.

doi:10.1016/j.jastp.2016.02.014

Cited by 10 publications

(5 citation statements)

References 49 publications

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“…The reported differences can reach as high as 2.5 ppmv (~46%) at 14.5 km (about 125 hPa) and are of about 1 ppmv (~ 25%) at 19 km (about 60 hPa). (Sunilkumar et al, 2016) have compared in-situ measurements of the NOAA cryogenic frost-point hygrometer with water vapor retrievals from MLS between 10 km (~260 hPa) and 24 km (~20 hPa) over India. The differences are of about 1 ppmv (~20 %) at 20 hPa with a minimum of 0.2 ppmv (~7%) at 80 hPa reaching a maximum of 100 ppmv (~40 %) in the upper troposphere.…”

Section: Water Vapormentioning

confidence: 99%

A lightweight balloon-borne mid-infrared hygrometer to probe the middle atmosphere: Pico-Light H2O. Comparison with Aura-MLS v4 and v5 satellite measurements

Ghysels

Durry

Amarouche³

et al. 2020

Preprint

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Abstract. Newly developed mid-infrared lightweight hygrometer, Pico-Light H2O has been tested in-flight on February 19, 2019 and October 16, 2019. It has been flown under a 1200 g rubber balloon operated by CNES from the Aire-sur-l'Adour facility (France) within the E.U. funded HEMERA WP11. During these two flights, we were able to obtain coincident MLS v4 and v5 water vapor and temperature profiles, leading to an inter-comparison between Pico-Light and Aura-MLS water vapor and temperature retrievals. Results from the comparison are in line with previous reported studies . Here, differences in the mid-latitude stratosphere and upper troposphere (20–316 hPa) are within 7 % and 64 % respectively. Largest differences with MLS v4 occurring within the upper troposphere nearby the cold point tropopause. The v5 MLS data have been corrected for observed dry bias nearby the tropopause, allowing to partially solve the observed discrepancies. Additionally, on February 19, the hygrometer has flown within an air filament from polar latitudes most of the flight for which a signature is observed on the water vapor profile and confirmed with ozone reanalysis from ERA 5and potential vorticity from MIMOSA advection model.

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Section: Water Vapormentioning

confidence: 99%

A lightweight balloon-borne mid-infrared hygrometer to probe the middle atmosphere: Pico-Light H2O. Comparison with Aura-MLS v4 and v5 satellite measurements

Ghysels

Durry

Amarouche³

et al. 2020

Preprint

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“…Figure 1 shown) shows the persistence of waves in the UTLS region on this day. There were several studies showing the influence of deep convection and waves on the temperature and water vapour in the UTLS region (eg: Suzuki et al, 2013;Sunilkumar et al, 2016;Muhsin et al, 2018). This cooler tropopause might be responsible for the freeze drying around this region resulting in a sharp minimum in WVMR close to the CPT.…”

Section: Altitude Distribution Of Lower Stratospheric Water Vapour Anmentioning

confidence: 99%

“…Several campaigns conducted in the tropical 10 regions have also addressed the variability of the UTLS water vapour using frost point hygrometers. (Sunilkumar et al, 2016). Trivandrum is an equatorial coastal station on the south west coast of Indian 15 peninsula and Hyderabad is an off equatorial inland station.…”

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confidence: 99%

Annual cycle of water vapour in the lower stratosphere over the Indian Peninsula derived from Cryogenic Frost-point Hygrometer observations

Emmanuel

Muhammed

Kumar

et al. 2018

Preprint

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Abstract. In situ measurements of lower stratospheric water vapour employing Cryogenic Frost point Hygrometer (CFH) over two tropical stations, Trivandrum (8.53&deg;N, 76.87&deg;E) and Hyderabad (17.47&deg;N, 78.58&deg;E) over the Indian subcontinent are conducted as part of Tropical Tropopause Dynamics (TTD) monthly campaigns under GARNETS program. The annual variation of lower stratosphere (LS) water vapour clearly depicts the so called tape recorder effect at both the stations. The ascent rate of water vapour compares well with the velocity of Brewer-Dobson circulation and is slightly higher over the equatorial station when compared to the off-equatorial station. The column integrated water vapour in the LS varies in the range 1.5 to 4g/m2 with low values during winter and high values during summer monsoon and post monsoon seasons and its variability shows the signatures of local dynamics. The variation in water vapour mixing ratio (WVMR) at the cold point tropopause (CPT) exactly follows the variation in CPT temperature. The difference in WVMR between the stations shows a semi-annual variability in the altitude region 18&ndash;20km region with high values of WVMR during summer monsoon and winter over Hyderabad and during pre-monsoon and post-monsoon over Trivandrum. This difference is related to the influence of the variations in local CPT temperature and deep convection. The monsoon dynamics has a significant role in stratospheric water vapour distribution in summer monsoon season.

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“…Radiosondes provide accurate temperature, relative humidity, and wind components (zonal and meridional winds) with a basic vertical resolution of 4–6 m (~1 s interval) from the surface up to an altitude of ~35 km. Accuracy of the measured wind is ~0.15 m/s and that of temperature is better than 0.5 K (Hurst et al, ; Sunilkumar et al, , ). The data sampled at ~1 s interval are subjected to strict quality check (abnormal profiles and the profiles with missing values for more than a kilometer are eliminated) and are averaged to a uniform vertical resolution of 100 m.…”

Section: Experimental Details and Data Analysismentioning

confidence: 99%

Seasonal and Diurnal Variations of Tropical Tropopause Layer (TTL) Over the Indian Peninsula

et al. 2017

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Seasonal and diurnal variations in the thermal structure of the troposphere and lower stratosphere with special reference to the tropical tropopause layer (TTL) are studied using data from 3 h interval radiosonde launches carried out simultaneously from Trivandrum (8.5°N, 76.9°E) and Gadanki (13.5°N,79°E) during December 2010 to March 2014. TTL is defined as the region extending from the level of minimum stability (LMinS) to the level of maximum stability (LMaxS). Above the cold point tropopause (CPT), temperature showed warm anomaly (4–5 K) during summer monsoon (June–September) and cold anomaly (up to −4 K) during winter (December–February). The temperature in the troposphere showed a clear diurnal variation (±0.5 K) with a cold anomaly during early morning and warm anomaly during the day in all the seasons. At Gadanki, the diurnal temperature anomaly in the lower stratosphere showed its phase propagating downward with time, whereas at Trivandrum such variations are not clearly evident. At diurnal timescales, the TTL showed significant variations at LMinS (0.5–1.5 km/5–7 K) and smaller variations at CPT (0.2–0.5 km/2–3 K). In general, the amplitude of the diurnal component is greater than the semidiurnal component for all the TTL parameters, and these amplitudes are relatively larger at Trivandrum than at Gadanki. The observed diurnal variations could be the manifestation of tidal oscillations and/or due to the influence of local convection. Correlation analysis between different TTL parameters indicated a slow transition from a governing adiabatic process in the TTL base to a diabatic process at the TTL top.

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Balloon-borne cryogenic frost-point hygrometer observations of water vapour in the tropical upper troposphere and lower stratosphere over India: First results

Cited by 10 publications

References 49 publications

A lightweight balloon-borne mid-infrared hygrometer to probe the middle atmosphere: Pico-Light H<sub>2</sub>O. Comparison with Aura-MLS v4 and v5 satellite measurements

A lightweight balloon-borne mid-infrared hygrometer to probe the middle atmosphere: Pico-Light H<sub>2</sub>O. Comparison with Aura-MLS v4 and v5 satellite measurements

Annual cycle of water vapour in the lower stratosphere over the Indian Peninsula derived from Cryogenic Frost-point Hygrometer observations

Seasonal and Diurnal Variations of Tropical Tropopause Layer (TTL) Over the Indian Peninsula

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Balloon-borne cryogenic frost-point hygrometer observations of water vapour in the tropical upper troposphere and lower stratosphere over India: First results

Cited by 10 publications

References 49 publications

A lightweight balloon-borne mid-infrared hygrometer to probe the middle atmosphere: Pico-Light H&lt;sub&gt;2&lt;/sub&gt;O. Comparison with Aura-MLS v4 and v5 satellite measurements

A lightweight balloon-borne mid-infrared hygrometer to probe the middle atmosphere: Pico-Light H&lt;sub&gt;2&lt;/sub&gt;O. Comparison with Aura-MLS v4 and v5 satellite measurements

Annual cycle of water vapour in the lower stratosphere over the Indian Peninsula derived from Cryogenic Frost-point Hygrometer observations

Seasonal and Diurnal Variations of Tropical Tropopause Layer (TTL) Over the Indian Peninsula

Contact Info

Product

Resources

About

A lightweight balloon-borne mid-infrared hygrometer to probe the middle atmosphere: Pico-Light H<sub>2</sub>O. Comparison with Aura-MLS v4 and v5 satellite measurements

A lightweight balloon-borne mid-infrared hygrometer to probe the middle atmosphere: Pico-Light H<sub>2</sub>O. Comparison with Aura-MLS v4 and v5 satellite measurements