Effects of Cumulus Entrainment and Multiple Cloud Types on a January Global Climate Model Simulation

Disaster damage caused by tropical cyclone has grown every year. However, our experience of tropical cyclone is not enough to evaluate very low frequent and catastrophic disaster event. Stochastic tropical cyclone model has been used for assessment of tropical cyclone disaster. Global stochastic model was improved by using a lot of ensemble Global Climate Model simulation data (d4PDF) instead of limited number of observation data. The model bias included d4PDF was corrected by each regional grid by simple statistical method and interpolation. The accuracy of new model was verified at representative regional area in different basins. Generally, the improvement is remarkable where tropical cyclones rarely passed. The variation of joint PDF of tropical cyclone change rate between previous model and present model agree with model improvement. As an example of application, the frequencies of strong tropical cyclone events of two cases were estimated.

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Response of Summer Precipitation over Eastern China to Large Volcanic Eruptions

Journal of Climate ◽

10.1175/2009jcli2950.1 ◽

2010 ◽

Vol 23 (3) ◽

pp. 818-824 ◽

Cited By ~ 34

Author(s):

Youbing Peng ◽

Caiming Shen ◽

Wei-Chyung Wang ◽

Ying Xu

Keyword(s):

Climate Model ◽

Model Simulation ◽

Global Climate ◽

Global Climate Model ◽

Regional Climate ◽

Eastern China ◽

Summer Precipitation ◽

Volcanic Eruptions ◽

Global Climate Model Simulation ◽

Large Volcanic Eruptions

Abstract Studies of the effects of large volcanic eruptions on regional climate so far have focused mostly on temperature responses. Previous studies using proxy data suggested that coherent droughts over eastern China are associated with explosive low-latitude volcanic eruptions. Here, the authors present an investigation of the responses of summer precipitation over eastern China to large volcanic eruptions through analyzing a 1000-yr global climate model simulation driven by natural and anthropogenic forcing. Superposed epoch analyses of 18 cases of large volcanic eruption indicate that summer precipitation over eastern China significantly decreases in the eruption year and the year after. Model simulation suggests that this reduction of summer precipitation over eastern China can be attributed to a weakening of summer monsoon and a decrease of moisture vapor over tropical oceans caused by large volcanic eruptions.

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Internal Variability of the Canadian RCM’s Hydrological Variables at the Basin Scale in Quebec and Labrador

Journal of Hydrometeorology ◽

10.1175/jhm-d-11-051.1 ◽

2012 ◽

Vol 13 (2) ◽

pp. 443-462 ◽

Cited By ~ 21

Author(s):

Marco Braun ◽

Daniel Caya ◽

Anne Frigon ◽

Michel Slivitzky

Keyword(s):

Climate Model ◽

Model Simulation ◽

Global Climate ◽

Global Climate Model ◽

Regional Climate ◽

Internal Variability ◽

Spectral Nudging ◽

Model Driven ◽

Basin Scale ◽

Hydrological Variables

Abstract The effect of a regional climate model’s (RCM’s) internal variability (IV) on climate statistics of annual series of hydrological variables is investigated at the scale of 21 eastern Canada watersheds in Quebec and Labrador. The analysis is carried out on 30-yr pairs of simulations (twins), performed with the Canadian Regional Climate Model (CRCM) for present (reanalysis and global climate model driven) and future (global climate model driven) climates. The twins differ only by the starting date of the regional simulation—a standard procedure used to trigger internal variability in RCMs. Two different domain sizes are considered: one comparable to domains used for RCM simulations over Europe and the other comparable to domains used for North America. Results for the larger North American domain indicate that mean relative differences between twin pairs of 30-yr climates reach ±5% when spectral nudging is used. Larger differences are found for extreme annual events, reaching about ±10% for 10% and 90% quantiles (Q10 and Q90). IV is smaller by about one order of magnitude in the smaller domain. Internal variability is unaffected by the period (past versus future climate) and by the type of driving data (reanalysis versus global climate model simulation) but shows a dependence on watershed size. When spectral nudging is deactivated in the large domain, the relative difference between pairs of 30-yr climate means almost doubles and approaches the magnitude of a global climate model’s internal variability. This IV at the level of the natural climate variability has a profound impact on the interpretation, analysis, and validation of RCM simulations over large domains.

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The Importance of the Zagros Mountains Barrier Jet to Future Precipitation in the Fertile Crescent

The Open Atmospheric Science Journal ◽

10.2174/1874282301105010087 ◽

2011 ◽

Vol 5 (1) ◽

pp. 87-95 ◽

Cited By ~ 7

Author(s):

J.P. Evans ◽

A. Alsamawi

Keyword(s):

Global Warming ◽

Water Vapour ◽

Climate Model ◽

Model Simulation ◽

Global Climate ◽

Global Climate Model ◽

Zagros Mountains ◽

Fertile Crescent ◽

Water Vapour Fluxes ◽

Precipitation Events

This study quantifies the significance of southerly water vapour fluxes, associated with the Zagros Mountains barrier jet, on precipitation occurring in the Eastern Fertile Crescent region and its change due to global warming. Precipitation events are simulated using a Regional Climate Model (MM5-Noah) driven by boundary conditions from a CCSM global climate model simulation with the SRES A2 emission scenario. The precipitation events were grouped into classes based on the similarity of their water vapour fluxes. Results show a massive increase in the southerly dominated classes which are associated with the formation of a barrier jet on the western slopes of the Zagros Mountains. This increase was related to an increase in atmospheric water vapour in the southern portion of the domain rather than to an increase in the frequency of formation or wind speed of the barrier jet itself. The presence of this barrier jet becomes increasingly important to precipitation in the Eastern Fertile Crescent region as global warming progresses. Thus, low resolution models that are unable to capture this phenomena will produce questionable future projections for this region.

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A new bias-correction method for precipitation over complex terrain suitable for different climate states: a case study using WRF (version 3.8.1)

Geoscientific Model Development ◽

10.5194/gmd-13-5007-2020 ◽

2020 ◽

Vol 13 (10) ◽

pp. 5007-5027

Author(s):

Patricio Velasquez ◽

Martina Messmer ◽

Christoph C. Raible

Keyword(s):

Regional Climate Model ◽

Bias Correction ◽

Complex Terrain ◽

Climate Model ◽

Model Simulation ◽

Global Climate ◽

Global Climate Model ◽

Regional Climate ◽

Correction Method ◽

Bias Correction Method

Abstract. This work presents a new bias-correction method for precipitation over complex terrain that explicitly considers orographic characteristics. This consideration offers a good alternative to the standard empirical quantile mapping (EQM) method during colder climate states in which the orography strongly deviates from the present-day state, e.g. during glacial conditions such as the Last Glacial Maximum (LGM). Such a method is needed in the event that absolute precipitation fields are used, e.g. as input for glacier modelling or to assess potential human occupation and according migration routes in past climate states. The new bias correction and its performance are presented for Switzerland using regional climate model simulations at 2 km resolution driven by global climate model outputs obtained under perpetual 1990 and LGM conditions. Comparing the present-day regional climate model simulation with observations, we find a strong seasonality and, especially during colder months, a height dependence of the bias in precipitation. Thus, we suggest a three-step correction method consisting of (i) a separation into different orographic characteristics, (ii) correction of very low intensity precipitation, and (iii) the application of an EQM, which is applied to each month separately. We find that separating the orography into 400 m height intervals provides the overall most reasonable correction of the biases in precipitation. The new method is able to fully correct the seasonal precipitation bias induced by the global climate model. At the same time, some regional biases remain, in particular positive biases over high elevated areas in winter and negative biases in deep valleys and Ticino in winter and summer. A rigorous temporal and spatial cross-validation with independent data exhibits robust results. The new bias-correction method certainly leaves some drawbacks under present-day conditions. However, the application to the LGM demonstrates that it is a more appropriate correction compared to the standard EQM under highly different climate conditions as the latter imprints present-day orographic features into the LGM climate.

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