Effects of topographic smoothing on the simulation of winter precipitation in High Mountain Asia

Cannon, Forest; Carvalho, Leila M. V.; Jones, Charles; Norris, Jesse; Bookhagen, Bodo; Kiladis, George N.

doi:10.1002/2016jd026038

Cited by 37 publications

(36 citation statements)

References 56 publications

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“…Based on our analysis, the extratropical RWS biases can be reduced by improving the simulation of local divergence/convergence pattern. Studies by Boos and Hurley (2012) and Cannon et al (2017) suggest that relatively coarse grid-scale climate models are unable to resolve the complex topography, which can give rise to biased representation of the regional divergence/convergence pattern, vertical motion, and resultant precipitation. The analysis in this study further implies that optimizing the representation of the topography or enhancing the horizontal resolution might be helpful in improving the model simulation of RWS in extratropics.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…The above result implies that representation of the topography may contribute to the local convergence bias. As suggested by previous studies, coarse grid-scale GCMs are unable to resolve the complex topography thus have a biased representation of the regional vertical motion and resultant precipitation (Boos & Hurley, 2012;Cannon et al, 2017). CMIP5 climate models typically have horizontal grid resolutions between 0.9°and 3°.…”

Section: Causes For the Rws Biases In East Asia And Western North Amementioning

confidence: 99%

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Winter and Summer Rossby Wave Sources in the CMIP5 Models

Nie

Zhang

Yang

et al. 2019

Earth and Space Science

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The Rossby wave source (RWS) in the upper troposphere plays an important role in the tropical‐extratropical teleconnections. Using the daily outputs from the Phase 5 of the Coupled Model Intercomparison Project (CMIP5) models, the overall model performances in simulating the climatological Rossby wave sources in both winter and summer are evaluated. The ensemble mean of the CMIP5 models can simulate the large‐scale geographical distributions of the RWS reasonably close to the observations, with the simulations of RWS in general better in the Southern Hemisphere. For the Northern Hemisphere, most models overestimate the subtropical RWS but underestimate the midlatitude RWS in both winter and summer. Many models even fail to simulate the seasonal source‐sink shift of RWS in East Asia. Greatest intermodel differences are shown in East Asia, western North America in both seasons, and in the subtropical belt in winter hemisphere. Possible reasons for the model biases in RWS are further investigated. In the Northern Hemisphere, our analysis shows that model performance in simulating the local divergence, which might relate to the overly smoothed topography in Asia and western North America in the model, is most responsible for the biases of the RWS simulations. In the Southern Hemisphere, the bias in subtropical divergence pattern and tropical convection all contribute to the intermodel divergence of RWS simulation.

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Section: Summary and Discussionmentioning

confidence: 99%

Section: Causes For the Rws Biases In East Asia And Western North Amementioning

confidence: 99%

Winter and Summer Rossby Wave Sources in the CMIP5 Models

Nie

Zhang

Yang

et al. 2019

Earth and Space Science

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“…Each sensitivity study represents 10‐year averaged equilibrium simulations that were ran for 16 years. We focus here on the summer monsoon season June, July, and August, although the winter IAM is also of great importance (Cannon et al, ; Forsythe et al, ; Holbourn et al, ). This study only looks at the steady‐state response to topographic forcing and does not touch upon seasonal initiation of the IAM (Park et al, ; Wu et al, ) or interannual variability during the monsoon season (Day et al, ; Dong et al, ).…”

Section: Scope Metrics and Experimentsmentioning

confidence: 99%

Competing Topographic Mechanisms for the Summer Indo‐Asian Monsoon

Acosta

Huber

2020

Geophysical Research Letters

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The Indo‐Asian Monsoon (IAM) has changed as the topographies of Asia were assembled into their current configuration. Understanding complex interactions between topography and the IAM through time has been hampered, in part, by poorly resolved topography and atmospheric dynamics in climate models. Here, we employ high‐resolution (0.23° × 0.31°) global climate simulations, to more accurately capture these interactions. We find that the Himalayas and Tibet primarily redirect the onshore moisture transport and produce local orographic precipitation. The Iranian Plateau is the primary gatekeeper, insulating the pool of high‐enthalpy air in the Indo‐Gangetic Plain (IGP) from westerly low‐enthalpy advection. But, even when such high‐enthalpy air exists along the IGP, vigorous precipitation in the region (poleward of 25°N) still requires orographic steering and lifting. The large‐scale circulations—largely governed by sea surface temperature gradients—robustly advect water vapor onshore regardless of topography. Thus, neither topography nor localized enthalpy air drives onshore monsoon flow.

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“…In this paper we consider two RCMs HIRHAM5 (Christensen et al, 2007) Dethloff et al (2010), while RACMO 21P forced by ERA-40 (ECMWF re-analysis of the global atmosphere and surface conditions for 45 years) was explored in Rodrigo et al (2013). van Wessem et al (2016) use RACMO2.3 to estimate background climate conditions in snow balance research over the Antarctic Peninsula.…”

Section: Introductionmentioning

confidence: 99%

Climate projections over the Antarctic Peninsula region to the end of the 21st century. Part II: wet/dry indices

Chyhareva¹,

Krakovska²,

Pishniak

2020

UAJ

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Objective of the study is an assessment of possible climate change in the region of the Antarctic Peninsula from 1986 until the end of the 21st century projected by the RCMs' ensemble. During the last decades Antarctica has undergone predominantly warming, with the highest rate of surface air temperature increase found over the Antarctic Peninsula, where the Ukrainian Antarctic Akademik Vernadsky station is located. There is a unique ecosystem in the region which is vulnerable and under the growing impact of a changing weather regime due to rapid climate changes with consequent changes in sea ice, land distribution under snow/ice, etc. Thus, an important task for the region is an estimation of climate change trends and definition of possible subregionalization. Data and methods. Data of two regional climate models HIRHAM5 and RACMO21P forced by two global climate models EC-EARTH and HadGEM from the Polar-CORDEX (Coordinated Regional Downscaling Experiment -Arctic and Antarctic Domains) as part of the international CORDEX initiative were used in the study. Spatial distribution of the model output is 0.44°. Set of scripting codes developed by Climate4R project (An R Framework for Climate Data Access and Postprocessing) was modified in order to extract data for the Antarctic Peninsula region from the Antarctic domain and obtain climatological characteristics for individual RCMs and their ensemble mean. Projected changes in wet/dry climate indices for scenarios RCP4.5 and RCP8.5 for two periods 2041-2060 and 2081-2100 were assessed with respect to the historical experiment 1986-2005. Results. An analysis of projected wet/dry climate indices for both RCP4.5 and RCP8.5 scenarios is presented in Part II of the paper. An analysis of the cold temperature indices (FD, ID) is presented in Part I of the study. In the historical experiment Larsen Ice Shelf and leeward east coast are the regions with the lowest total precipitation in wet days (PRCPTOT, 200-300 mm) and simple daily intensity index (SDII, about 5 mm/day) with under 10 days of consecutive wet days (CWD) and up to 30 days consecutive dry days (CDD). In the cross of the 21st century, duration of dry spell is projected to shorten for the whole peninsula and for Akademik Vernadsky station by about 7-10% under the scenario RCP4.5 and 10-15% under the RCP8.5. Projected SDII changes are up to +20% till the end of the century under the scenario RCP8.5 at north-west coast of the Antarctic Peninsula. Conclusions. Over the Antarctic Peninsula region both scenarios project an average increase in total PRCPTOT and SDII; overall the maximum length of CWD is extended while the maximum length of the CDD is reduced. In combination with decreasing number of frost (FD) and ice (ID) days, the pattern of changes differs notably across the peninsula. It is shown in the first part of the paper that over the Antarctic Peninsula region, both scenarios project an average decrease in the cold season period. The most pronounced changes of ID and FD climate indices are for the Larsen Ice Sh...

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Effects of topographic smoothing on the simulation of winter precipitation in High Mountain Asia

Cited by 37 publications

References 56 publications

Winter and Summer Rossby Wave Sources in the CMIP5 Models

Winter and Summer Rossby Wave Sources in the CMIP5 Models

Competing Topographic Mechanisms for the Summer Indo‐Asian Monsoon

Climate projections over the Antarctic Peninsula region to the end of the 21st century. Part II: wet/dry indices

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