The NCEP Climate Forecast System Version 2

Saha, Sujata; Moorthi, Shrinivas; Wu, Xuan; Wang, Jiande; Nadiga, Sudhir; Tripp, Patrick; Behringer, David; Hou, Yu-Tai; Chuang, Hui Ya; Iredell, Mark; Ek, Michael; Meng, Jesse; Yang, Rongqian; Peña, M.; Dool, Huug van den; Zhang, Qin; Wang, Wanqiu; Chen, Mingyue; Becker, Emily

doi:10.1175/jcli-d-12-00823.1

Cited by 2,840 publications

(2,112 citation statements)

References 21 publications

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“…The atmosphere and ocean exchange quantities such as heat and momentum fluxes every half an hour, with no flux adjustment or correction. See Saha et al 69 for further details on the model and its components. The coupled configuration of CFSv2 is time integrated over a period of 100 years, and utilized as the reference run (CFSv2 CTL ).…”

Section: Methodsmentioning

confidence: 99%

Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient

et al. 2015

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There are large uncertainties looming over the status and fate of the South Asian summer monsoon, with several studies debating whether the monsoon is weakening or strengthening in a changing climate. Our analysis using multiple observed datasets demonstrates a significant weakening trend in summer rainfall during 1901-2012 over the central-east and northern regions of India, along the Ganges-Brahmaputra-Meghna basins and the Himalayan foothills, where agriculture is still largely rain-fed. Earlier studies have suggested an increase in moisture availability and land-sea thermal gradient in the tropics due to anthropogenic warming, favouring an increase in tropical rainfall. Here we show that the land-sea thermal gradient over South Asia has been decreasing, due to rapid warming in the Indian Ocean and a relatively subdued warming over the subcontinent. Using long-term observations and coupled model experiments, we provide compelling evidence that the enhanced Indian Ocean warming potentially weakens the land-sea thermal contrast, dampens the summer monsoon Hadley circulation, and thereby reduces the rainfall over parts of South Asia.

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Section: Methodsmentioning

confidence: 99%

Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient

et al. 2015

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“…go.jp/jma/jma-eng/jma-center/nwp/outline2013-nwp/index. htm); and the NCEP model (Saha et al, 2010(Saha et al, , 2014. Table 1 summarizes the model information and details of the hindcasts.…”

Section: Onset and Demise Dates Of The Rainy Season In Hindcastsmentioning

confidence: 99%

Sub-seasonal Predictability of the Onset and Demise of the Rainy Season over Monsoonal Regions

et al. 2017

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Sub-seasonal to seasonal (S2S) retrospective forecasts from three global coupled models are used to evaluate the predictability of the onset and demise dates of the rainy season over monsoonal regions. The onset and demise dates of the rainy season are defined using only precipitation data. The forecasts of the onset and demise dates of the rainy season are based on a hybrid methodology that combines observations and simulations. Although skillful model precipitation predictions remain challenging in many regions, our results show that they are skillful enough to identify onset and demise dates of the rainy season in many monsoon regions at sub-seasonal (∼30 days) lead-times in retrospective forecasts. We verify sub-seasonal prediction skill for the onset and demise dates of the rainy season over South America, East Asia, and Northern Australia. However, we find low prediction skill for the onset and demise of the rainy season on sub-seasonal scales over the Indian monsoon region. This information would be valuable to sectors related to water management.

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“…The parameterizations of physical processes have been substantially revised to match those used in the NCEP Climate Forecast System version 2 (CFSv2; Saha et al 2014). The surface fluxes are calculated based on Miyakoda and Sirutis (1986).…”

Section: Overview Of the Cwb Agcmmentioning

confidence: 99%

A Source of AGCM Bias in Simulating the Western Pacific Subtropical High: Different Sensitivities to the Two Types of ENSO

Paek

Hwu³

et al. 2015

Monthly Weather Review

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This study reveals a possible cause of model bias in simulating the western Pacific subtropical high (WPSH) variability via an examination of an Atmospheric Model Intercomparison Project (AMIP) simulation produced by the atmospheric general circulation model (AGCM) developed at Taiwan's Central Weather Bureau (CWB). During boreal summer, the model overestimates the quasi-biennial (2-3 yr) band of WPSH variability but underestimates the low-frequency (3-5 yr) band of variability. The overestimation of the quasibiennial WPSH sensitivity is found to be due to the model's stronger sensitivity to the central Pacific El Niño-Southern Oscillation (CP ENSO) that has a leading periodicity in the quasi-biennial band. The model underestimates the low-frequency WPSH variability because of its weaker sensitivity to the eastern Pacific (EP) ENSO that has a leading periodicity in the 3-5-yr band. These different model sensitivities are shown to be related to the relative strengths of the mean Hadley and Walker circulations simulated in the model. An overly strong Hadley circulation causes the CWB AGCM to be overly sensitive to the CP ENSO, while an overly weak Walker circulation results in a weak sensitivity to the EP ENSO. The relative strengths of the simulated mean Hadley and Walker circulations are critical to a realistic simulation of the summer WPSH variability in AGCMs. This conclusion is further supported using AMIP simulations produced by three other AGCMs, including the CanAM4, GISS-E2-R, and IPSL-CM5A-MR models.

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The NCEP Climate Forecast System Version 2

Cited by 2,840 publications

References 21 publications

Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient

Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient

Sub-seasonal Predictability of the Onset and Demise of the Rainy Season over Monsoonal Regions

A Source of AGCM Bias in Simulating the Western Pacific Subtropical High: Different Sensitivities to the Two Types of ENSO

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