Meridional distribution of moisture transport associated to Tropical Cyclones

2020 ◽  
Author(s):  
Daniele Peano ◽  
Enrico Scoccimarro ◽  
Alessio Bellucci ◽  
Malcolm Roberts ◽  
Annalisa Cherchi ◽  
...  
Keyword(s):  
Water Vapor ◽  
High Resolution ◽  
Tropical Cyclones ◽  
Moisture Transport ◽  
Climate Models ◽  
Climate Model ◽  
Water Vapor Transport ◽  
The North ◽  
Good Ability ◽  
The Impact

<p>Tropical cyclones (TCs) transport energy and moisture along their pathways interacting with the climate system and TCs activities are expected to extend further poleward during the 21<sup>st</sup> century.</p><p>For this reason, it is important to assess the ability of state-of-the-art climate models in reproducing an accurate meridional distribution of TCs as well as a reasonable meridional portrait of moisture transport associated with TCs.</p><p>Since high resolutions are required to reconstruct observed TCs activity, the present work is based on the simulations performed as part of HighResMIP in the framework of the community CMIP6 effort. To inspect this feature, two horizontal resolutions for each climate model are considered. Besides, the impact of boundary conditions, i.e. observed ocean surface state, is examined by considering both coupled and atmosphere-only configurations.</p><p>In the present work, the north Atlantic region is analyzed as a sample region, while the same approach is applied on a multi-basin basis. In the sample area, climate models present a good ability in reproducing the TCs distribution, with a general underestimation at lower latitudes and a slight overestimation at high-latitudes compared to observed TCs tracks (e.g. IBTRACK).</p><p>The meridional distribution of moisture transport associated with TCs is evaluated by considering the radial average of the integrated water vapor transport along the TC tracks. When compared to observation (IBTRACS and JRA-55 reanalysis), the simulated moisture transport associated with TCs displays reasonably good performance in atmosphere-only high-resolution models configuration. The interannual variability of water vapor associated with TCs, instead, is poorly represented in climate models.</p><p>Climate models in high-resolution configuration can then be used in estimating future TCs meridional distribution and changes in meridional moisture transport associated with TCs.</p><p>This effort is part of HighResMIP and it is developed in the framework of the EU-funded PRIMAVERA project.   </p>

scholarly journals Effect of tropical cyclones on the Stratosphere-Troposphere Exchange observed using satellite observations over north Indian Ocean

2016 ◽  
Author(s):  
M. Venkat Ratnam ◽  
S. Ravindra Babu ◽  
S. S. Das ◽  
Ghouse Basha ◽  
B. V. Krishnamurthy ◽  
...  
Keyword(s):  
Water Vapor ◽  
Indian Ocean ◽  
Tropical Cyclones ◽  
Lower Stratosphere ◽  
North Indian Ocean ◽  
Satellite Observations ◽  
Upper Troposphere ◽  
North West ◽  
The North ◽  
The Impact

Abstract. Tropical cyclones play an important role in modifying the tropopause structure and dynamics as well as stratosphere-troposphere exchange (STE) process in the Upper Troposphere and Lower Stratosphere (UTLS) region. In the present study, the impact of cyclones that occurred over the North Indian Ocean during 2007–2013 on the STE process is quantified using satellite observations. Tropopause characteristics during cyclones are obtained from the Global Positioning System (GPS) Radio Occultation (RO) measurements and ozone and water vapor concentrations in UTLS region are obtained from Aura-Microwave Limb Sounder (MLS) satellite observations. The effect of cyclones on the tropopause parameters is observed to be more prominent within 500 km from the centre of cyclone. In our earlier study we have observed decrease (increase) in the tropopause altitude (temperature) up to 0.6 km (3 K) and the convective outflow level increased up to 2 km. This change leads to a total increase in the tropical tropopause layer (TTL) thickness of 3 km within the 500 km from the centre of cyclone. Interestingly, an enhancement in the ozone mixing ratio in the upper troposphere is clearly noticed within 500 km from cyclone centre whereas the enhancement in the water vapor in the lower stratosphere is more significant on south-east side extending from 500–1000 km away from the cyclone centre. We estimated the cross-tropopause mass flux for different intensities of cyclones and found that the mean flux from stratosphere to troposphere for cyclonic stroms is 0.05 ± 0.29 × 10−3 kg m−2 and for very severe cyclonic stroms it is 0.5 ± 1.07 × 10−3 kg m−2. More downward flux is noticed in the north-west and south-west side of the cyclone centre. These results indicate that the cyclones have significant impact in effecting the tropopause structure, ozone and water vapour budget and consequentially the STE in the UTLS region.

scholarly journals Changes in Winter Atmospheric Rivers along the North American West Coast in CMIP5 Climate Models

2015 ◽  
Vol 16 (1) ◽  
pp. 118-128 ◽  
Author(s):  
Michael D. Warner ◽  
Clifford F. Mass ◽  
Eric P. Salathé
Keyword(s):  
Water Vapor ◽  
North American ◽  
West Coast ◽  
American West ◽  
Climate Models ◽  
Water Vapor Transport ◽  
The West ◽  
North American West ◽  
The North ◽  
Extreme Precipitation Events

Abstract Most extreme precipitation events that occur along the North American west coast are associated with winter atmospheric river (AR) events. Global climate models have sufficient resolution to simulate synoptic features associated with AR events, such as high values of vertically integrated water vapor transport (IVT) approaching the coast. From phase 5 of the Coupled Model Intercomparison Project (CMIP5), 10 simulations are used to identify changes in ARs impacting the west coast of North America between historical (1970–99) and end-of-century (2070–99) runs, using representative concentration pathway (RCP) 8.5. The most extreme ARs are identified in both time periods by the 99th percentile of IVT days along a north–south transect offshore of the coast. Integrated water vapor (IWV) and IVT are predicted to increase, while lower-tropospheric winds change little. Winter mean precipitation along the west coast increases by 11%–18% [from 4% to 6% (°C)−1], while precipitation on extreme IVT days increases by 15%–39% [from 5% to 19% (°C)−1]. The frequency of IVT days above the historical 99th percentile threshold increases as much as 290% by the end of this century.

scholarly journals The Impact of the Sierra Nevada on Low-Level Winds and Water Vapor Transport

2007 ◽  
Vol 8 (4) ◽  
pp. 790-804 ◽  
Author(s):  
Jinwon Kim ◽  
Hyun-Suk Kang
Keyword(s):  
Water Vapor ◽  
Sierra Nevada ◽  
Climate Model ◽  
Northern Region ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Western Slope ◽  
Mountain Range ◽  
Low Level ◽  
The Impact

Abstract To understand the influence of the Sierra Nevada on the water cycle in California the authors have analyzed low-level winds and water vapor fluxes upstream of the mountain range in regional climate model simulations. In a low Froude number (Fr) regime, the upstream low-level wind disturbances are characterized by the rapid weakening of the crosswinds and the appearance of a stagnation point over the southwestern foothills. The weakening of the low-level inflow is accompanied by the development of along-ridge winds that take the form of a barrier jet over the western slope of the mountain range. Such upstream wind disturbances are either weak or nonexistent in a high-Fr case. A critical Fr (Frc) of 0.35 inferred in this study is within the range of those suggested in previous observational and numerical studies. The depth of the blocked layer estimated from the along-ridge wind profile upstream of the northern Sierra Nevada corresponds to Frc between 0.3 and 0.45 as well. Associated with these low-level wind disturbances are significant low-level southerly moisture fluxes over the western slope and foothills of the Sierra Nevada in the low-Fr case, which result in significant exports of moisture from the southern Sierra Nevada to the northern region. This along-ridge low-level water vapor transport by blocking-induced barrier jets in a low-Fr condition may result in a strong north–south precipitation gradient over the Sierra Nevada.

scholarly journals North Atlantic gyre circulation in PRIMAVERA models

2021 ◽  
Author(s):  
Virna L. Meccia ◽  
Doroteaciro Iovino ◽  
Alessio Bellucci
Keyword(s):  
High Resolution ◽  
North Atlantic ◽  
Climate Models ◽  
Horizontal Resolution ◽  
Meridional Overturning Circulation ◽  
The North ◽  
Ocean Response ◽  
The North Atlantic ◽  
Gyre Circulation ◽  
The Impact

AbstractWe study the impact of horizontal resolution in setting the North Atlantic gyre circulation and representing the ocean–atmosphere interactions that modulate the low-frequency variability in the region. Simulations from five state-of-the-art climate models performed at standard and high-resolution as part of the High-Resolution Model Inter-comparison Project (HighResMIP) were analysed. In some models, the resolution is enhanced in the atmospheric and oceanic components whereas, in some other models, the resolution is increased only in the atmosphere. Enhancing the horizontal resolution from non-eddy to eddy-permitting ocean produces stronger barotropic mass transports inside the subpolar and subtropical gyres. The first mode of inter-annual variability is associated with the North Atlantic Oscillation (NAO) in all the cases. The rapid ocean response to it consists of a shift in the position of the inter-gyre zone and it is better captured by the non-eddy models. The delayed ocean response consists of an intensification of the subpolar gyre (SPG) after around 3 years of a positive phase of NAO and it is better represented by the eddy-permitting oceans. A lagged relationship between the intensity of the SPG and the Atlantic Meridional Overturning Circulation (AMOC) is stronger in the cases of the non-eddy ocean. Then, the SPG is more tightly coupled to the AMOC in low-resolution models.

Real-Time Track Prediction of Tropical Cyclones over the North Indian Ocean Using the ARW Model

2013 ◽  
Vol 52 (11) ◽  
pp. 2476-2492 ◽  
Author(s):  
Krishna K. Osuri ◽  
U. C. Mohanty ◽  
A. Routray ◽  
M. Mohapatra ◽  
Dev Niyogi
Keyword(s):  
High Resolution ◽  
Indian Ocean ◽  
Real Time ◽  
Tropical Cyclones ◽  
North Indian Ocean ◽  
Track Forecast ◽  
Forecast Errors ◽  
The North ◽  
Arw Model ◽  
The Impact

AbstractThe performance of the Advanced Research version of the Weather Research and Forecasting (ARW) model in real-time prediction of tropical cyclones (TCs) over the north Indian Ocean (NIO) at 27-km resolution is evaluated on the basis of 100 forecasts for 17 TCs during 2007–11. The analyses are carried out with respect to 1) basins of formation, 2) straight-moving and recurving TCs, 3) TC intensity at model initialization, and 4) season of occurrence. The impact of high resolution (18 and 9 km) on TC prediction is also studied. Model results at 27-km resolution indicate that the mean track forecast errors (skill with reference to persistence track) over the NIO were found to vary from 113 to 375 km (7%–51%) for a 12–72-h forecast. The model showed a right/eastward and slow bias in TC movement. The model is more skillful in track prediction when initialized at the intensity stage of severe cyclone or greater than at the intensity stage of cyclone or lower. The model is more efficient in predicting landfall location than landfall time. The higher-resolution (18 and 9 km) predictions yield an improvement in mean track error for the NIO Basin by about 4%–10% and 8%–24%, respectively. The 9-km predictions were found to be more accurate for recurving TC track predictions by ~13%–28% and 5%–15% when compared with the 27- and 18-km runs, respectively. The 9-km runs improve the intensity prediction by 15%–40% over the 18-km predictions. This study highlights the capabilities of the operational ARW model over the Indian monsoon region and the continued need for operational forecasts from high-resolution models.

scholarly journals A Mechanism of Internal Decadal Atlantic Ocean Variability in a High-Resolution Coupled Climate Model

2015 ◽  
Vol 28 (19) ◽  
pp. 7764-7785 ◽  
Author(s):  
Matthew B. Menary ◽  
Daniel L. R. Hodson ◽  
Jon I. Robson ◽  
Rowan T. Sutton ◽  
Richard A. Wood
Keyword(s):  
High Resolution ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
Climate Models ◽  
Climate Model ◽  
Heat Content ◽  
Coupled Climate Model ◽  
North Atlantic Current ◽  
The North ◽  
The North Atlantic

Abstract The North Atlantic Ocean subpolar gyre (NA SPG) is an important region for initializing decadal climate forecasts. Climate model simulations and paleoclimate reconstructions have indicated that this region could also exhibit large, internally generated variability on decadal time scales. Understanding these modes of variability, their consistency across models, and the conditions in which they exist is clearly important for improving the skill of decadal predictions—particularly when these predictions are made with the same underlying climate models. This study describes and analyzes a mode of internal variability in the NA SPG in a state-of-the-art, high-resolution, coupled climate model. This mode has a period of 17 yr and explains 15%–30% of the annual variance in related ocean indices. It arises because of the advection of heat content anomalies around the NA SPG. Anomalous circulation drives the variability in the southern half of the NA SPG, while mean circulation and anomalous temperatures are important in the northern half. A negative feedback between Labrador Sea temperatures/densities and those in the North Atlantic Current (NAC) is identified, which allows for the phase reversal. The atmosphere is found to act as a positive feedback on this mode via the North Atlantic Oscillation (NAO), which itself exhibits a spectral peak at 17 yr. Decadal ocean density changes associated with this mode are driven by variations in temperature rather than salinity—a point which models often disagree on and which may affect the veracity of the underlying assumptions of anomaly-assimilating decadal prediction methodologies.

scholarly journals Response of Global Tropical Cyclone Activity to Increasing CO2: Results from Downscaling CMIP6 Models

2021 ◽  
Vol 34 (1) ◽  
pp. 57-70 ◽  
Author(s):  
Kerry Emanuel
Keyword(s):  
Tropical Cyclone ◽  
Greenhouse Gases ◽  
Tropical Cyclones ◽  
Climate Models ◽  
Climate Model ◽  
Tropical Cyclone Activity ◽  
Cmip5 Models ◽  
Cyclone Activity ◽  
The North ◽  
Sixth Generation

AbstractGlobal models comprising the sixth-generation Coupled Climate Model Intercomparison Project (CMIP6) are downscaled using a very high-resolution but simplified coupled atmosphere–ocean tropical cyclone model, as a means of estimating the response of global tropical cyclone activity to increasing greenhouse gases. As with a previous downscaling of CMIP5 models, the results show an increase in both the frequency and severity of tropical cyclones, robust across the models downscaled, in response to increasing greenhouse gases. The increase is strongly weighted to the Northern Hemisphere, and especially noteworthy is a large increase in the higher latitudes of the North Atlantic. Changes are insignificant in the South Pacific across metrics. Although the largest increases in track density are far from land, substantial increases in global landfalling power dissipation are indicated. The incidence of rapid intensification increases rapidly with warming, as predicted by existing theory. Measures of robustness across downscaled climate models are presented, and comparisons to tropical cyclones explicitly simulated in climate models are discussed.

scholarly journals The effect of geographic sampling on evaluation of extreme precipitation in high-resolution climate models

2020 ◽  
Vol 6 (2) ◽  
pp. 115-139
Author(s):  
Mark D. Risser ◽  
Michael F. Wehner
Keyword(s):  
High Resolution ◽  
Observational Data ◽  
Climate Models ◽  
Climate Model ◽  
Horizontal Resolution ◽  
Global Climate Models ◽  
Boreal Winter ◽  
Weather Stations ◽  
High Resolution Models ◽  
The Impact

Abstract. Traditional approaches for comparing global climate models and observational data products typically fail to account for the geographic location of the underlying weather station data. For modern global high-resolution models with a horizontal resolution of tens of kilometers, this is an oversight since there are likely grid cells where the physical output of a climate model is compared with a statistically interpolated quantity instead of actual measurements of the climate system. In this paper, we quantify the impact of geographic sampling on the relative performance of high-resolution climate model representations of precipitation extremes in boreal winter (December–January–February) over the contiguous United States (CONUS), comparing model output from five early submissions to the HighResMIP subproject of the CMIP6 experiment. We find that properly accounting for the geographic sampling of weather stations can significantly change the assessment of model performance. Across the models considered, failing to account for sampling impacts the different metrics (extreme bias, spatial pattern correlation, and spatial variability) in different ways (both increasing and decreasing). We argue that the geographic sampling of weather stations should be accounted for in order to yield a more straightforward and appropriate comparison between models and observational data sets, particularly for high-resolution models with a horizontal resolution of tens of kilometers. While we focus on the CONUS in this paper, our results have important implications for other global land regions where the sampling problem is more severe.

High-Resolution Climate Change Impact Analysis on Expected Future Water Availability in the Upper Jordan Catchment and the Middle East

2014 ◽  
Vol 15 (4) ◽  
pp. 1517-1531 ◽  
Author(s):  
Gerhard Smiatek ◽  
Harald Kunstmann ◽  
Andreas Heckl
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Water Availability ◽  
Impact Analysis ◽  
River Flow ◽  
Climate Model ◽  
Mesoscale Model ◽  
Global Climate Model ◽  
Full Range ◽  
The Impact

Abstract The impact of climate change on the future water availability of the upper Jordan River (UJR) and its tributaries Dan, Snir, and Hermon located in the eastern Mediterranean is evaluated by a highly resolved distributed approach with the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) run at 18.6- and 6.2-km resolution offline coupled with the Water Flow and Balance Simulation Model (WaSiM). The MM5 was driven with NCEP reanalysis for 1971–2000 and with Hadley Centre Coupled Model, version 3 (HadCM3), GCM forcings for 1971–2099. Because only one regional–global climate model combination was applied, the results may not give the full range of possible future projections. To describe the Dan spring behavior, the hydrological model was extended by a bypass approach to allow the fast discharge components of the Snir to enter the Dan catchment. Simulation results for the period 1976–2000 reveal that the coupled system was able to reproduce the observed discharge rates in the partially karstic complex terrain to a reasonable extent with the high-resolution 6.2-km meteorological input only. The performed future climate simulations show steadily rising temperatures with 2.2 K above the 1976–2000 mean for the period 2031–60 and 3.5 K for the period 2070–99. Precipitation trends are insignificant until the middle of the century, although a decrease of approximately 12% is simulated. For the end of the century, a reduction in rainfall ranging between 10% and 35% can be expected. Discharge in the UJR is simulated to decrease by 12% until 2060 and by 26% until 2099, both related to the 1976–2000 mean. The discharge decrease is associated with a lower number of high river flow years.

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

Atmosphere ◽  
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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