Implementation of Noah land surface model advances in the National Centers for Environmental Prediction operational mesoscale Eta model

Ek, Michael; Mitchell, Kenneth E.; Ying, Lin; Rogers, Eric; Grunmann, Pablo Javier; Koren, Victor; Gayno, George; Tarpley, J. Dan

doi:10.1029/2002jd003296

Cited by 2,674 publications

(1,920 citation statements)

References 52 publications

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“…1) with the simulated cases located in the central United States. The model physical configuration is that described in Aligo et al (2007) with the exception of the planetary boundary layer (PBL) scheme and the land surface model (LSM), which in the present study are, respectively, the Mellor-Yamada-Janjic (MYJ; Janjic 2002) scheme and the land surface model Noah (Ek et al 2003). In addition to the above configuration, the 12-km outer nest used the Betts-Miller-Janjic convective scheme (Betts 1986;Betts and Miller 1986;Janjic 1994), which currently is employed operationally at the National Centers for Environmental Prediction (NCEP).…”

Section: Methodsology a Model Setup And Datamentioning

confidence: 99%

On the Impact of WRF Model Vertical Grid Resolution on Midwest Summer Rainfall Forecasts

Aligo

Gallus

Segal

2009

Weather and Forecasting

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Weather Research and Forecast (WRF) model exploratory sensitivity simulations were performed to determine the impact of vertical grid resolution (VGR) on the forecast skill of Midwest summer rainfall. Varying the VGR indicated that a refined VGR, while adopting the widely used North America Regional Reanalysis (NARR) for initial and lateral boundary conditions, does not necessarily result in a consistent improvement in quantitative precipitation forecasts (QPFs). When averaged over a variety of microphysical schemes in an illustrative case, equitable threat score (ETS) and bias values actually worsened with a greater overpredicted rainfall for half of the rainfall thresholds when the VGR was refined. Averaged over strongly forced cases, ETS values worsened for all rainfall thresholds while biases mostly increased, indicating a further overprediction of rainfall when the number of levels was increased. Skill improved, however, for all rainfall thresholds when the resolution above the melting level was increased. Skill also improved for most rainfall thresholds when the resolution in the surface layer was increased, which is attributed to better-resolved surface turbulent momentum and thermal fluxes. Likewise, a refined VGR resulted in improvements in weakly forced cases, which are governed mostly by thermodynamic forcing and are sensitive to vertical profiles of temperature and moisture. Application of the factor separation method suggested that the refined VGR more frequently had a negative impact on skill through the interaction between lower-atmospheric processes and microphysical processes above the melting level. KeywordsAgronomy, atmospheric process, equitable threat score, illustrative case, lateral boundary conditions, melting levels, microphysical process, negative impacts, quantitative precipitation forecast, reanalysis, sensitivity simulation, summer rainfall, surface layers, thermal fluxes, turbulent momentum, vertical grids, WRF model, atmospheric thermodynamics, climate prediction, rainfall, weather forecasting Varying the VGR indicated that a refined VGR, while adopting the widely used North America Regional Reanalysis (NARR) for initial and lateral boundary conditions, does not necessarily result in a consistent improvement in quantitative precipitation forecasts (QPFs). When averaged over a variety of microphysical schemes in an illustrative case, equitable threat score (ETS) and bias values actually worsened with a greater overpredicted rainfall for half of the rainfall thresholds when the VGR was refined. Averaged over strongly forced cases, ETS values worsened for all rainfall thresholds while biases mostly increased, indicating a further overprediction of rainfall when the number of levels was increased. Skill improved, however, for all rainfall thresholds when the resolution above the melting level was increased. Skill also improved for most rainfall thresholds when the resolution in the surface layer was increased, which is attributed to better-resolved surface turbulent momentum ...

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Section: Methodsology a Model Setup And Datamentioning

confidence: 99%

On the Impact of WRF Model Vertical Grid Resolution on Midwest Summer Rainfall Forecasts

Aligo

Gallus

Segal

2009

Weather and Forecasting

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“…While the physics sensitivity experiment will be explored more fully in Part II, we will also reference herein results using the Noah (Chen and Dudhia 2001;Ek et al 2003) and thermal diffusion (TD; Skamarock et al 2008) LSMs, and the Yonsei University (YSU; Hong et al 2006), Mellor-Yamada-Janjic (MYJ) PBL scheme (Janjic 1994), and total energy-mass flux (TEMF; Angevine et al 2010) PBL parameterizations. In particular, the Noah-YSU combination, along with the surface layer scheme derived from MM5 (Noah-YSU), 7 is of interest because it is likely the most commonly used configuration in WRF.…”

Section: B Model Experimental Designmentioning

confidence: 99%

Downslope Windstorms of San Diego County. Part I: A Case Study

Yang

Fovell

2016

Monthly Weather Review

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The “Santa Ana” wind is an offshore flow that affects Southern California periodically during the winter half of the year, typically between September and May. The winds can be locally gusty, particularly in the complex terrain of San Diego County, where the winds have characteristics of downslope windstorms. These winds can cause and/or rapidly spread wildfires, the threat of which is particularly acute during the autumn season before the onset of winter rains. San Diego’s largest fires, including the Cedar fire of 2003 and Witch Creek fire of 2007, occurred during Santa Ana wind events. A case study of downslope flow during a moderately intense Santa Ana event during mid-February 2013 is presented. Motivated by the need to forecast winds impinging on electrical lines, the authors make use of an exceptionally dense network of near-surface observations in San Diego County to calibrate and verify simulations made utilizing the Advanced Research version of the Weather Research and Forecasting (WRF) Model, which in turn is employed to augment the observations. Results demonstrate that this particular Santa Ana episode consists of two pulses separated by a protracted lull. During the first pulse, the downslope flow is characterized by a prominent hydraulic jumplike feature, while during the second one the flow possesses a clear temporal progression of winds downslope. WRF has skill in capturing the evolution and magnitude of the event at most locations, although most model configurations overpredict the observed sustained wind and the forecast bias is itself biased.

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“…The atmospheric boundary layer is calculated based on the simple model of Troen and Mahrt (1986). The land surface scheme used is the four-layer Noah scheme (Ek et al 2003). Radiative transfer is calculated following Liou (1992, 1993) and Fu et al (1997).…”

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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Implementation of Noah land surface model advances in the National Centers for Environmental Prediction operational mesoscale Eta model

Cited by 2,674 publications

References 52 publications

On the Impact of WRF Model Vertical Grid Resolution on Midwest Summer Rainfall Forecasts

On the Impact of WRF Model Vertical Grid Resolution on Midwest Summer Rainfall Forecasts

Downslope Windstorms of San Diego County. Part I: A Case Study

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

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