Abbreviations and terminology

Abbreviations

	3DDA Three-dimensional data assimilation, using only those observations available at the time of analysis (Wiki)
	4DDA / nudging	Four-dimensional data assimilation, using also observations available at a later time than the time of analysis
	ABL	Atmospheric Boundary Layer
	AOML-HRD	NOAA Atlantic Oceanographic and Meteorological Laboratory  Hurricane Research Division
	ARW	Advanced Research WRF
	BB	Big Brother (outer domain) (Køltzow-2008)
	C or TC	Tropical Cyclone(s)
	CHASM	The chameleon land surface model was among the earliest efforts to explore the impact of model complexity on model performance.
	cpp	C Preprocessor Program
	DTC	Developmental Testbed Center, located in Boulder, CO
	EC data	Data from ECMWF in Reading, UK
	ECMWF MARS	Meteorological archive retrieval system (data archive)
	EMC, NRL, NCEP	Environmental Modeling Center
	ERA	ECMWF Reanalysis
	ERA-15	The first project, ERA-15 (1979-1993)
	ERA-40	the second extended reanalysis project, ERA-40 (1957-2002)
	ERA-Interim	A data assimilation system that uses a 2006 release of the Integrated Forecasting System (IFS Cy31r2), which contains many improvements both in the forecasting model and analysis methodology relative to ERA-40.
	ESRL	Earth System Research Laboratory
	ET	Extratropical Transition
	FIFE	Observed suface fluxes from the First International ISLSCP Field Experiment
	FTE	Forecast Track Error
	GCM	Global Climate Model or General Circulation Model
	GDAS	Global Data Assimilation System (NCEP product)
	GFDL	Geophysical Fluid Dynamics Laboratory
	GFS	Global Forecast System  (NCEP product)
	GLACE	Global Land‐Atmosphere Coupling Experiment (Koster-2006)
	GRIP	Gridded binary (a certain format)
	GSWP	Global soil wetness project  (se Niu-2011)
	HFIP	Hurricane Forecast Improvement Project
	HIRLAM	High-resolution limited area model
	HRLDAS	The High Resolution Land Data Assimilation System
	HWRF	Hurricane Weather Research and Forecasting Model
	HWRFx	Experimental HWRF developed by the AOML-HRD
	IFS	Integrated Forecasting System, method used in reanalysis at ECMWF
	IPCC	Intergovernmental Panel on Climate Change
	ISLSCP	Satellite Land Surface Climatology Project
	LSM	Land Surface Model(s)
	MFC	Moisture Flux Convergence
	MODIS NASA	Moderate Resolution Imaging Spectroradiometer
	MSLP	Mean Sea Level Pressure described in millibars
	MYJ	Mellor-Yamada-Janjic PBL parameterization in the WRF model
	NAM	North American Model (covers continental united states)
	NASA	National Aeronautics and Space Administration
	NCAR	National Center for Atmospheric Research
	NCEP	National Center for Environmental Prediction
	NDAS	NAM Data Assimilation System (covers continental united states)
	NESDIS	National Environmental Satellite, Data and Information Service, Center for Satellite Applications and Research
	NMM	Non-hydrostatic Mesoscale Model
	NMM	Nonhydrostatic Mesoscale Mode
	NOAA	National Oceanic and Atmospheric Administration
	NOAH	NOAH is an acronym of acronyms for the contributing offices that helped develop the land surface model. N=NCEP,  O=Oregon State University (Dept. of Atmospheric Sciences),  A=Air Force (AF Weather Agency and AF Research Lab),  H=NWS Hydrologic Research Lab
	Noah V3 	Noah version 3.0
	Noah-MP	a framework for multiple options to parameterize selected processes (Niu-2011). Newer version than Noah LSM 3.0.
	NWP	Numerical Weather Prediction
	NWS	National Weather Service
	PAR	photosynthetically active radiation (see Niu-2011)
	PBE	Perfect Boundary Experiment (Christensen, J.H et al 1997 Clim Dyn 11 p 3204)
	PBL	Planetary Boundary Layer
	PIPLS	Project for Intercomparison of Land Surface Parameterization Schemes (se Niu-2011)
	POM	Princeton Ocean Model
	RAL	Research Applications Laboratory at NCAR
	RCM	Regional Climate Model
	RegClim	Regional Climate Development Under Global Warming (Norwegian research project 1997-2006)
	SST	Sea Surface Temperature
	SZA	Solar Zenith Angle (see Niu-2011)
	TS	Tropical Storm
	USGS	United States Geological Survey
	WFD	Watch Forcing Data
	WFDEI	Watch Forcing Data-Era Interim
	WPS	WRF Pre-processing System
	WRF	Weather Research and Forecasting Model
	YSU	Yonsei University PBL scheme in the WRF model

Terminology

	Analysis 	the production of an accurate image of the true state of the atmosphere at a given time represented in a model as a collection of numbers ("Data assimilation concepts and methods" by F. Bouttier and P. Courtier).
	Assimilation	Data assimilation is an analysis technique in which the observed information is accumulated into the model state by taking advantage of consistency constraints with laws of time evolution and physical properties. ("Data assimilation concepts and methods" by F. Bouttier and P. Courtier).
	Climate mode	Let the model run for a long time using one set of input. Is updated at the boundaries (SST every hour), but can drift a lot in the middle.
	domain	
	Dynamical	a model is involved
	Forecast mode	Every 7.th or 14.th day, the simulations are started anew with observations in all grid points, not just at the boundaries, and not just using SST.
	Nesting	Different domains having different resolution. The outer nest is an odd number greater than the inner.
	Nudging (4DDA)	(tuning) force the large-scale phenomena to be reproduced, and let the small-scale effects develop.
	Offline	Can force the model using WFDEI or ERA-Interim to avoid chaotic states, but the drawback is that the land surface cannot feed back to the atmosphere. 
	parameter space	see Gulden et al. 2008
	Parameterization	the process of deciding and defining the parameters necessary for a complete or relevant specification of a model. (Wiki)  In a weather or climate model within numerical weather prediction refers to the method of replacing processes that are too small-scale or complex to be physically represented in the model by a simplified process. (Wiki) parametrization_(climate)
	Predictability	the degree to which a correct prediction or forecast of a system's state can be made either qualitatively or quantitatively. (Wiki)
	Reanalysis	Uses a global NWP to combine simulations and observations and fill in data in all gridpoints. 
	WPS-geogrid	defines model domains and interpolates static geographical data to the grids. Purpose: to define the simulation domains, and interpolate various terrestrial data sets to the model grids.
	WPS-metgrid	horizontally interpolates the meteorological fields extracted by ungrib to the model grids defined by geogrid. 
	WPS-real.exe	"program for real-data simulations. The work of vertically interpolating meteorological fields to WRF eta levels is performed within the real program."	WPS-ungrib	extracts meteorological fields from GRIB-formatted files