Relaxed Arakawa-Schubert. A Parameterization of Moist Convection for General Circulation Models

Moorthi, Shrinivas; Suárez, Max J.

doi:10.1175/1520-0493(1992)120<0978:rasapo>2.0.co;2

Cited by 957 publications

(633 citation statements)

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“…Radiative transfer is calculated following Liou (1992, 1993) and Fu et al (1997). Cumulus convection is parameterized by a relaxed Arakawa-Schubert (RAS) parameterization scheme (Moorthi and Suarez 1992). The large-scale precipitation is calculated using the Zhao and Carr (1997) scheme and shallow convection is parameterized using the scheme of Li (1994).…”

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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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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“…The CLWP from IRS-P4 provided by the NRSA have been analyzed and compared with the values obtained from the NCMRWF global model having a Relaxed Arakawa-Schubert (RAS) convection scheme (Moorthi and Suarez, 1992). The numerical model has been used to produce 6 hours forecast starting from 00 UTC initial conditions of 1-20 August 1999.…”

Section: Methodsmentioning

confidence: 99%

“…A description of the NCMRWF model can be seen in Das (1996). The CLWP has been diagnosed using the RAS cumulus parameterization based on Moorthi and Suarez (1992). RAS assumes that all liquid water formed inside a cloud is carried to the top where it is detrained.…”

Section: Derivation Of Clwp From the Modelmentioning

confidence: 99%

Study of cloud liquid water path and total precipitable water from irs-p4/msmr and numerical weather prediction model output

Das

Rao

Mohanty

et al. 2004

J Indian Soc Remote Sens

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A global weather analysis-forecast system is used to produce six hourly analysis of meteorological fields at roughly 150 km x 150 km resolution at the National Center for Medium Range Weather Forecast (NCMRWF). In this paper, we have studied the Total Precipitable Water Content (TPWC) and Cloud Liquid Water Path (CLWP) derived from the Indian Remote Sensing (IRS-P4) Satellite over the Indian Ocean region in relation to operational numerical weather prediction (NWP) model analysis and short-range forecasts. An objective analysis was carried out by introducing the observations of CLWP, TPWC and their values (six hour forecasts) from the T80 model as the first guess, for a 20 days period of August 1999 using the standard Cressman's technique. The reanalysis could capture the signature of TPWC and CLWP data from IRS-P4 satellite. In general the observed values of TPWC and CLWP from IRS-P4 have a positive bias compared to NCMRWF analysis over the region where the satellite passed. The CLWP values have been compared with Special Sensor Microwave/Imager (SSM/I) products from the Defense Meteorological Satellite Program (DMSP) satellites. Results indicate that the model derived CLWP values were within acceptable limits, whereas the observations from the Multi-channel Scanning Microwave Radiometer (MSMR) showed slightly larger values.

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“…The CWF is a metric of atmospheric stability and in the SAS scheme the CWF has to reach a critical value in order for convection to occur. The CWF critical value which gives the best performance in the model depends on a convective adjustment timescale [Moorthi and Suarez, 1992] that assumes different values over land and ocean and is also highly dependent on the pressure difference in the original initial trigger criterion in the SAS scheme. This relationship between the initial and the CWF criteria might be related to the fact that the New SAS improved the forecast skill and the representation of convection in the CFSv2, but it also increased the surface temperature bias in comparison to Old SAS [Han and Pan, 2011].…”

Section: Journal Of Advances In Modeling Earth Systems 101002/2016msmentioning

confidence: 99%

The heated condensation framework as a convective trigger in the NCEP Climate Forecast System version 2

Bombardi

Tawfik

Manganello

et al. 2016

J Adv Model Earth Syst

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An updated version of the Heated Condensation Framework (HCF) is implemented as a convective triggering criterion into the National Centers for Environmental Prediction (NCEP) Climate Forecast System version 2 (CFSv2). The new trigger replaces the original criteria in both the deep (Simplified Arakawa‐Schubert – SAS) and shallow (SAS based) convective schemes. The performance of the original and new triggering criteria is first compared against radiosonde observations. Then, a series of hindcasts are performed to evaluate the influence of the triggering criterion in the CFSv2 representation of summer precipitation, the diurnal cycle of precipitation, and hurricanes that made landfall. The observational analysis shows that the HCF trigger better captures the frequency of convection, where the original SAS trigger initiates convection too often. When implemented in CFSv2, the HCF trigger improves the seasonal forecast of the Indian summer monsoon rainfall, including the representation of the onset dates of the rainy season over India. On the other hand, the HCF trigger increases error in the seasonal forecast of precipitation over the eastern United States. The HCF trigger also improves the representation of the intensity of hurricanes. Moreover, the simulation of hurricanes provides insights on the mechanism whereby the HCF trigger impacts the representation of convection.

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Relaxed Arakawa-Schubert. A Parameterization of Moist Convection for General Circulation Models

Cited by 957 publications

References 0 publications

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

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

Study of cloud liquid water path and total precipitable water from irs-p4/msmr and numerical weather prediction model output

The heated condensation framework as a convective trigger in the NCEP Climate Forecast System version 2

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