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

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.

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

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.

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

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.

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

2016 ◽  
Vol 9 (3) ◽  
pp. 1207-1219 ◽  
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.

scholarly journals Enhanced Stratospheric Water Vapor over the Summertime Continental United States and the Role of Overshooting Convection

2016 ◽  
Author(s):  
Robert L. Herman ◽  
Eric A. Ray ◽  
Karen H. Rosenlof ◽  
Kristopher M. Bedka ◽  
Michael J. Schwartz ◽  
...  
Keyword(s):  
United States ◽  
Water Vapor ◽  
The United States ◽  
Atmospheric Composition ◽  
North American Monsoon ◽  
Back Trajectory ◽  
Stratospheric Water Vapor ◽  
Mixing Ratios ◽  
The North ◽  
Back Trajectory Analysis

Abstract. The NASA ER-2 aircraft sampled the UTLS region over North America during the NASA Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field mission. This study reports three case studies of convectively-influenced air parcels with enhanced water vapor in the overworld stratosphere over the summertime continental United States. Water vapor mixing ratios greater than 10 ppmv, more than twice the stratospheric background levels, were measured by the JPL Laser Hygrometer (JLH Mark2) at pressure levels between 80 and 160 hPa. Through satellite observations and analysis, we make the connection between these in situ water measurements and overshooting cloud tops. The overshooting tops (OT) are identified from a SEAC4RS OT detection product based on satellite infrared window channel brightness temperature gradients. Back trajectory analysis ties enhanced water to OT one to seven days prior to the intercept by the aircraft. The trajectory paths are dominated by the North American Monsoon (NAM) anticyclonic circulation. This connection suggests that ice is convectively transported to the overworld stratosphere in OT events and subsequently sublimated; such events may irreversibly enhance stratospheric water vapor in the summer over Mexico and the United States. Regional context is provided by water observations from the Aura Microwave Limb Sounder (MLS).

scholarly journals Effect of the Indo-Pacific Warm Pool on Lower-Stratospheric Water Vapor and Comparison with the Effect of ENSO

2018 ◽  
Vol 31 (3) ◽  
pp. 929-943 ◽  
Author(s):  
Fei Xie ◽  
Xin Zhou ◽  
Jianping Li ◽  
Quanliang Chen ◽  
Jiankai Zhang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Climate Model ◽  
Southern Oscillation ◽  
Deep Convection ◽  
Warm Pool ◽  
Latent Heat Release ◽  
Stratospheric Water Vapor ◽  
Asymmetric Effects ◽  
Pacific Warm Pool ◽  
Tropopause Temperature

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.

scholarly journals CMIP5 Simulations of Low-Level Tropospheric Temperature and Moisture over the Tropical Americas

2013 ◽  
Vol 26 (17) ◽  
pp. 6257-6286 ◽  
Author(s):  
Leila M. V. Carvalho ◽  
Charles Jones
Keyword(s):  
Daily Precipitation ◽  
Monsoon Season ◽  
Coupled Model ◽  
Specific Humidity ◽  
Cmip5 Models ◽  
North American Monsoon ◽  
Tropospheric Temperature ◽  
The North ◽  
Decadal Variations ◽  
Monsoon System

Abstract Global warming has been linked to systematic changes in North and South America's climates and may severely impact the North American monsoon system (NAMS) and South American monsoon system (SAMS). This study examines interannual-to-decadal variations and changes in the low-troposphere (850 hPa) temperature (T850) and specific humidity (Q850) and relationships with daily precipitation over the tropical Americas using the NCEP–NCAR reanalysis, the Climate Forecast System Reanalysis (CFSR), and phase 5 of the Coupled Model Intercomparison Project (CMIP5) simulations for two scenarios: “historic” and high-emission representative concentration pathway 8.5 (RCP8.5). Trends in the magnitude and area of the 85th percentiles were distinctly examined over North America (NA) and South America (SA) during the peak of the respective monsoon season. The historic simulations (1951–2005) and the two reanalyses agree well and indicate that significant warming has occurred over tropical SA with a remarkable increase in the area and magnitude of the 85th percentile in the last decade (1996–2005). The RCP8.5 CMIP5 ensemble mean projects an increase in the T850 85th percentile of about 2.5°C (2.8°C) by 2050 and 4.8°C (5.5°C) over SA (NA) by 2095 relative to 1955. The area of SA (NA) with T850 ≥ the 85th percentile is projected to increase from ~10% (15%) in 1955 to ~58% (~33%) by 2050 and ~80% (~50%) by 2095. The respective increase in the 85th percentile of Q850 is about 3 g kg−1 over SAMS and NAMS by 2095. CMIP5 models project variable changes in daily precipitation over the tropical Americas. The most consistent is increased rainfall in the intertropical convergence zone in December–February (DJF) and June–August (JJA) and decreased precipitation over NAMS in JJA.

scholarly journals A Numerical Investigation of Wet and Dry Onset Modes in the North American Monsoon Core Region. Part I: A Regional Mechanism for Interannual Variability

2012 ◽  
Vol 25 (11) ◽  
pp. 3953-3969 ◽  
Author(s):  
Cuauhtémoc Turrent ◽  
Tereza Cavazos
Keyword(s):  
Interannual Variability ◽  
Diurnal Cycle ◽  
North American ◽  
Gulf Of California ◽  
Deep Convection ◽  
Core Region ◽  
Eastern Pacific ◽  
North American Monsoon ◽  
The Core ◽  
The North

In this study the results of two regional fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) simulations forced at their boundaries with low-pass-filtered North American Regional Reanalysis (NARR) composite fields from which synoptic-scale variability was removed are presented. The filtered NARR data are also assimilated into the inner domain through the use of field nudging. The purpose of this research is to investigate wet and dry onset modes in the core region of the North American monsoon (NAM). Key features of the NAM that are present in the NARR fields and assimilated into the regional simulations include the position of the midlevel anticyclone, low-level circulation over the Gulf of California, and moisture flux patterns into the core monsoon region, for which the eastern Pacific is the likely primary source of moisture. The model develops a robust diurnal cycle of deep convection over the peaks of the Sierra Madre Occidental (SMO) that results solely from its radiation scheme and internal dynamics, in spite of the field nudging. The wet onset mode is related to a regional land–sea thermal contrast (LSTC) that is ~2°C higher than in the dry mode, and is further characterized by a northward-displaced midlevel anticyclone, a stronger surface pressure gradient along the Gulf of California, larger mean moisture fluxes into the core region from the eastern Pacific, a stronger diurnal cycle of deep convection, and the more northward distribution of precipitation along the axis of the SMO. A proposed regional LSTC mechanism for NAM onset interannual variability is consistent with the differences between both onset modes.

Revisiting the factors that drive interannual variability in stratospheric entry water vapour

2020 ◽  
Author(s):  
Shlomi Ziskin Ziv ◽  
Chaim I. Garfinkel
Keyword(s):  
Water Vapor ◽  
Interannual Variability ◽  
Large Scale ◽  
Trace Gases ◽  
Transport Processes ◽  
Tropospheric Temperature ◽  
Stratospheric Water Vapor ◽  
Cold Point ◽  
Stratospheric Trace Gases

&lt;p&gt;Understanding the sinks, sources and transport processes of stratospheric trace gases can improve our prediction of mid to long term climate change. In this study we consider the processes that lead to variability in stratospheric water vapor. We perform a Multiple Linear Regression(MLR) on the SWOOSH combined anomaly filled water vapor product with ENSO, QBO, BDC, mid-tropospheric temperature, and CH4 as predictors, in an attempt to find the factors that most succinctly explain observed water vapor variability. We also consider the fraction of entry water vapor variability that can be accounted for by variations of the cold point temperature as an upper bound on how much water vapor variability is predictable from large scale processes. Several periods in which the MLR fails to account for interannual variability are treated as case studies in order to better understand variability in entry water not governed by these large scale processes.&lt;/p&gt;

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