Slayt 1 - RTC, Regional Training Centre - Turkey

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1- NWP EquationsIn NWP, future values of meteorological variables are solved for by finding their initial values and thenadding the physical forcing that acts on the variables over the time period of the forecast. This is statedaswhere F(A) stands for the combination of all of the kinds of forcing that can occur.This stepwise process represents the configuration of the prediction equations used in NWP. Thespecific forecast equations used in NWP models are called the primitive equations (not because theyare crude or simplistic, but because they describe the fundamental processes that occur in theatmosphere). These equations govern the motion and thermodynamic changes that occur in theatmosphere and are derived from the complete conservation laws of momentum, mass, energy, andmoisture.The way in which primitive equations are derived from their complete theoretical form and convertedto computer codes can contribute to forecast errors in NWP models.1. The model forecast equations are simplified versions of the actual physical laws governing atmosphericprocesses, especially cloud processes, land-atmosphere exchanges, and radiation. The physical anddynamic approximations in these equations limit the phenomena that can be predicted.2. Due to their complexity, the primitive equations must be solved numerically using algebraicapproximations, rather than calculating complete analytic solutions. These numerical approximationsintroduce error even when the forecast equations completely describe the phenomenon of interest andeven if the initial state were perfectly represented.3. Computer translations of the model forecast equations cannot contain all details at all resolutions.Therefore, some information about atmospheric fields will be missing or misrepresented in the modeleven if perfect observations were available and the initial state of the atmosphere were known exactly.4. Grid point and spectral methods are techniques for representing information about atmosphericvariables in the model and solving the set of forecast equations. Each technique introduces differenttypes of errors.The ways in which NWP models produce forecast guidance and introduce forecast errors are exploredfurther throughout the rest of the Model Type section.
2-The Primitive Equations For forecasting purposes, this set of equations is consideredto be closed and complete (meaning that we can forecastvalues of all terms by solving each of the equations in theproper sequence) since All equations use the same basic forecast variables (u, v, , T,q, and z) The terms Fx, Fy, H, E, and P can also be described in termsof the six basic forecast variables We can specify initial conditions over the domain of themodel We can obtain suitable boundary conditions for all forecastvariables at the boundaries of the model
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ATMOSPHERIC MODELINGNUMERICAL WEATH
Page 3 and 4:
MTO477Brief History of Meteorology
Page 5:
Excerpts from Aristotle’sMeteorol
Page 72: The Forces of a Parcel of Air
Page 84 and 85: Atmospheric Model Aerosol processes
Page 86 and 87: Highlights 1955 - First Operational
Page 88 and 89: Highlights 1996 - AVN/MRF changed t
Page 90 and 91: Highlights2001 (November) - Major c
Page 92 and 93: Equivalent-Barotropic Atmosphere Co
Page 94 and 95: Thermal Wind (Remember?)The thermal
Page 96 and 97: Written in general form:tAiA i = de
Page 98 and 99: Example of a diagnostic equation:Co
Page 100 and 101: NUMERICAL WEATHER PREDICTIONLECTURE
Page 102 and 103: Model ComponentsForecast:This repre
Page 104 and 105: Model ComponentsDynamics:In NWP, dy
Page 106 and 107: Parameterized Processes and Paramet
Page 108 and 109: Parameterizing Sub Grid-Scale Proce
Page 110 and 111: Accounting for the Effects of Physi
Page 112 and 113: Outlook As computer power increases
Page 114 and 115: DiscussionThe correct choices are (
Page 118 and 119: 2-The Primitive Equations
Page 120 and 121: Horizontal advection of west-to-eas
Page 122 and 123: Additional Information: Coriolis Fo
Page 124 and 125: Additional Information: Coriolis Fo
Page 126 and 127: Temperature Forecast EquationTime c
Page 128 and 129: Hydrostatic or Vertical MomentumEqu
Page 130 and 131: Physical ProcessesAll of the foreca
Page 132 and 133: How Models Solve the ForecastEquati
Page 134 and 135: Representing the Forecast Variables
Page 136 and 137: 3-Grid Point: Data RepresentationGr
Page 138 and 139: 4-Grid Point ModelsIn the real atmo
Page 140 and 141: 5- SPECTRAL MODELHow Data are Repre
Page 142 and 143: Use of Grid Point Methods in Spectr
Page 144 and 145: Impacts of Grid Point Physics Calcu
Page 146 and 147: 7- Hydrostatic Models Most grid poi
Page 148 and 149: Non-Hydrostatic Models In addition,
Page 151 and 152: HYDROSTATIC MODELS Characteristics
Page 153 and 154: References Carr, F.H., 1988: Introd
Page 155 and 156: The dependent variables in this set
Page 157 and 158: Problems in finding suitable latera
Page 159 and 160: Conditions whichOnemakeBIGthe primi
Page 161 and 162: Courant-Friederichs-Lewy criteria C
Page 163 and 164: Setting up a Numerical Model Grid p
Page 165 and 166: Horizontal resolution Horizontal re
Page 167 and 168:
Sigma Coordinate System (σ)p• De
Page 169 and 170:
Convective ParameterizationSchemes
Page 171:
«Computations indicate that a perf
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Slayt 1 - RTC, Regional Training Centre - Turkey

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