Evaluating the influence of deep convection on tropopause thermodynamics and lower stratospheric water vapor: A RELAMPAGO case study using the WRF model

Abstract Time-slice experiments with the Whole Atmosphere Community Climate Model, version 4 (WACCM4), and composite analysis with satellite observations are used to demonstrate that the Indo-Pacific warm pool (IPWP) can significantly affect lower-stratospheric water vapor. It is found that a warmer IPWP significantly dries the stratospheric water vapor by causing a broad cooling of the tropopause, and vice versa for a colder IPWP. Such imprints in tropopause temperature are driven by a combination of variations in the Brewer–Dobson circulation in the stratosphere and deep convection in the troposphere. Changes in deep convection associated with El Niño–Southern Oscillation (ENSO) reportedly have a small zonal mean effect on lower-stratospheric water vapor for strong zonally asymmetric effects on tropopause temperature. In contrast, IPWP events have zonally uniform imprints on tropopause temperature. This is because equatorial planetary waves forced by latent heat release from deep convection project strongly onto ENSO but weakly onto IPWP events.

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Intercomparison of in situ water vapor balloon-borne measurements from Pico-SDLA H<sub>2</sub>O and FLASH-B in the tropical UTLS

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-8-13693-2015 ◽

2015 ◽

Vol 8 (12) ◽

pp. 13693-13727

Author(s):

M. Ghysels ◽

E. D. Riviere ◽

S. Khaykin ◽

C. Stoeffler ◽

N. Amarouche ◽

...

Keyword(s):

Water Vapor ◽

Low Cost ◽

Deep Convection ◽

Mixing Ratio ◽

Stratospheric Water Vapor ◽

In Situ Techniques ◽

Scientific Project ◽

Water Vapor Mixing Ratio ◽

The Impact

Abstract. In this paper we compare water vapor mixing ratio measurements from two quasi-parallel flights of the Pico-SDLA H2O and FLASH-B hygrometers. The measurements were made on 10 February 2013 and 13 March 2012, respectively, in the tropics near Bauru, Sao Paulo St., Brazil during an intense convective period. Both flights were performed as part of a French scientific project, TRO-Pico, to study the impact of the deep-convection overshoot on the water budget. Only a few instruments that permit the frequent sounding of stratospheric water vapor can be flown within a small volume weather balloons. Technical difficulties preclude the accurate measurement of stratospheric water vapor with conventional in situ techniques. The instruments described here are simple and lightweight, which permits their low-cost deployment by non-specialists aboard a small weather balloon. We obtain mixing ratio retrievals which agree above the cold-point tropopause to within 1.9 and 0.5 % for the first and second flights, respectively. This level of agreement for measured stratospheric water mixing ratio is among the best ever reported in the literature. Because both instruments show similar profiles within their combined uncertainties, we conclude that the Pico-SDLA H2O and FLASH-B datasets are mutually consistent.

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Influence of convection on stratospheric water vapor in the North American Monsoon region

10.5194/acp-2020-405 ◽

2020 ◽

Author(s):

Wandi Yu ◽

Andrew Dessler ◽

Mijeong Park ◽

Eric Jensen

Keyword(s):

Water Vapor ◽

Deep Convection ◽

High Water ◽

North American Monsoon ◽

Valuable Insight ◽

Tropospheric Temperature ◽

Central Plains ◽

Stratospheric Water Vapor ◽

The North ◽

Water Vapor Mixing Ratio

Abstract. We quantify the connection between deep convection occurrence and summertime 100-hPa water vapor anomaly over the North America (NA) region and find substantial consistency of their interannual variations and that the water vapor mixing ratio over the NA region is up to ~ 1 ppmv higher when deep convection occurs. We use a Lagrangian trajectory model to demonstrate that the structure and the location of the NA anticyclone, as well as the tropical upper tropospheric temperature, determine how much contribution the deep convection could make to moistening the lower stratosphere. The deep convection mainly occurs over the Central Plains region, and most of the convectively moistened air is then transported to the center of the NA anticyclone and the anticyclonic structure helps maintain high water vapor content there. Our hypothesis explains both the summer seasonal cycle and interannual variability of the convective moistening efficiency in the NA region, and can provide valuable insight on modeling stratospheric water vapor.

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Intercomparison of in situ water vapor balloon-borne measurements from Pico-SDLA H<sub>2</sub>O and FLASH-B in the tropical UTLS

Atmospheric Measurement Techniques ◽

10.5194/amt-9-1207-2016 ◽

2016 ◽

Vol 9 (3) ◽

pp. 1207-1219 ◽

Cited By ~ 3

Author(s):

Mélanie Ghysels ◽

Emmanuel D. Riviere ◽

Sergey Khaykin ◽

Clara Stoeffler ◽

Nadir Amarouche ◽

...

Keyword(s):

Water Vapor ◽

Low Cost ◽

Deep Convection ◽

Data Sets ◽

Mixing Ratio ◽

Stratospheric Water Vapor ◽

In Situ Techniques ◽

Water Vapor Mixing Ratio ◽

The Impact

Abstract. In this paper we compare water vapor mixing ratio measurements from two quasi-parallel flights of the Pico-SDLA H2O and FLASH-B hygrometers. The measurements were made on 10 February 2013 and 13 March 2012, respectively, in the tropics near Bauru, São Paulo state, Brazil during an intense convective period. Both flights were performed as part of a French scientific project, TRO-Pico, to study the impact of the deep-convection overshoot on the water budget. Only a few instruments that permit the frequent sounding of stratospheric water vapor can be flown within small-volume weather balloons. Technical difficulties preclude the accurate measurement of stratospheric water vapor with conventional in situ techniques. The instruments described here are simple and lightweight, which permits their low-cost deployment by non-specialists aboard a small weather balloon. We obtain mixing ratio retrievals which agree above the cold-point tropopause to within 1.9 and 0.5 % for the first and second flights, respectively. This level of agreement for balloon-borne measured stratospheric water mixing ratio constitutes one of the best agreement reported in the literature. Because both instruments show similar profiles within their combined uncertainties, we conclude that the Pico-SDLA H2O and FLASH-B data sets are mutually consistent.

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Influence of convection on stratospheric water vapor in the North American monsoon region

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-12153-2020 ◽

2020 ◽

Vol 20 (20) ◽

pp. 12153-12161

Author(s):

Wandi Yu ◽

Andrew E. Dessler ◽

Mijeong Park ◽

Eric J. Jensen

Keyword(s):

Water Vapor ◽

North American ◽

Deep Convection ◽

High Water ◽

North American Monsoon ◽

Valuable Insight ◽

Tropospheric Temperature ◽

Stratospheric Water Vapor ◽

The North ◽

Water Vapor Mixing Ratio

Abstract. We quantify the connection between deep convective occurrence and summertime 100 hPa water vapor anomaly over the North American (NA) region and find substantial consistency between their interannual variations and also that the water vapor mixing ratio over the NA region is up to ∼1 ppmv higher when deep convection occurs. We use a Lagrangian trajectory model to demonstrate that the structure and the location of the NA anticyclone, as well as the tropical upper tropospheric temperature, mediate the moistening impact of convection. The deep convection mainly occurs over the Central Plains region. Most of the convectively moistened air is then transported to the center of the NA anticyclone, and the anticyclonic structure helps maintain high water vapor content there. This explains both the summer seasonal cycle and interannual variability of the convective moistening efficiency in the NA region and can provide valuable insight into modeling stratospheric water vapor.

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Impacts of Ozone Changes in the Tropopause Layer on Stratospheric Water Vapor

Atmosphere ◽

10.3390/atmos12030291 ◽

2021 ◽

Vol 12 (3) ◽

pp. 291

Author(s):

Jinpeng Lu ◽

Fei Xie ◽

Hongying Tian ◽

Jiali Luo

Keyword(s):

Water Vapor ◽

Ozone Depletion ◽

Climate Model ◽

Global Climate ◽

Stratospheric Water Vapor ◽

Radiative Processes ◽

Low Latitudes ◽

Cold Point ◽

The Impact ◽

Tropopause Temperature

Stratospheric water vapor (SWV) changes play an important role in regulating global climate change, and its variations are controlled by tropopause temperature. This study estimates the impacts of tropopause layer ozone changes on tropopause temperature by radiative process and further influences on lower stratospheric water vapor (LSWV) using the Whole Atmosphere Community Climate Model (WACCM4). It is found that a 10% depletion in global (mid-low and polar latitudes) tropopause layer ozone causes a significant cooling of the tropical cold-point tropopause with a maximum cooling of 0.3 K, and a corresponding reduction in LSWV with a maximum value of 0.06 ppmv. The depletion of tropopause layer ozone at mid-low latitudes results in cooling of the tropical cold-point tropopause by radiative processes and a corresponding LSWV reduction. However, the effect of polar tropopause layer ozone depletion on tropical cold-point tropopause temperature and LSWV is opposite to and weaker than the effect of tropopause layer ozone depletion at mid-low latitudes. Finally, the joint effect of tropopause layer ozone depletion (at mid-low and polar latitudes) causes a negative cold-point tropopause temperature and a decreased tropical LSWV. Conversely, the impact of a 10% increase in global tropopause layer ozone on LSWV is exactly the opposite of the impact of ozone depletion. After 2000, tropopause layer ozone decreased at mid-low latitudes and increased at high latitudes. These tropopause layer ozone changes at different latitudes cause joint cooling in the tropical cold-point tropopause and a reduction in LSWV. Clarifying the impacts of tropopause layer ozone changes on LSWV clearly is important for understanding and predicting SWV changes in the context of future global ozone recovery.

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Features and trends in Atmospheric Trace Molecule Spectroscopy (ATMOS) version 3 stratospheric water vapor and methane measurements

Journal of Geophysical Research Atmospheres ◽

10.1029/2000jd900336 ◽

2000 ◽

Vol 105 (D18) ◽

pp. 22713-22724 ◽

Cited By ~ 38

Author(s):

H. A. Michelsen ◽

F. W. Irion ◽

G. L. Manney ◽

G. C. Toon ◽

M. R. Gunson

Keyword(s):

Water Vapor ◽

Stratospheric Water Vapor

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Evaluation of the WRF Model to Simulate a High-Intensity Rainfall Event over Kampala, Uganda

Water ◽

10.3390/w13060873 ◽

2021 ◽

Vol 13 (6) ◽

pp. 873

Author(s):

Yakob Umer ◽

Janneke Ettema ◽

Victor Jetten ◽

Gert-Jan Steeneveld ◽

Reinder Ronda

Keyword(s):

High Intensity ◽

Flood Hazard ◽

Weather Prediction ◽

Wrf Model ◽

Numerical Weather Prediction Model ◽

Rainfall Event ◽

Weather Research And Forecasting ◽

Event Triggering ◽

Rain Events

Simulating high-intensity rainfall events that trigger local floods using a Numerical Weather Prediction model is challenging as rain-bearing systems are highly complex and localized. In this study, we analyze the performance of the Weather Research and Forecasting (WRF) model’s capability in simulating a high-intensity rainfall event using a variety of parameterization combinations over the Kampala catchment, Uganda. The study uses the high-intensity rainfall event that caused the local flood hazard on 25 June 2012 as a case study. The model capability to simulate the high-intensity rainfall event is performed for 24 simulations with a different combination of eight microphysics (MP), four cumulus (CP), and three planetary boundary layer (PBL) schemes. The model results are evaluated in terms of the total 24-h rainfall amount and its temporal and spatial distributions over the Kampala catchment using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) analysis. Rainfall observations from two gauging stations and the CHIRPS satellite product served as benchmark. Based on the TOPSIS analysis, we find that the most successful combination consists of complex microphysics such as the Morrison 2-moment scheme combined with Grell-Freitas (GF) and ACM2 PBL with a good TOPSIS score. However, the WRF performance to simulate a high-intensity rainfall event that has triggered the local flood in parts of the catchment seems weak (i.e., 0.5, where the ideal score is 1). Although there is high spatial variability of the event with the high-intensity rainfall event triggering the localized floods simulated only in a few pockets of the catchment, it is remarkable to see that WRF is capable of producing this kind of event in the neighborhood of Kampala. This study confirms that the capability of the WRF model in producing high-intensity tropical rain events depends on the proper choice of parametrization combinations.

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