Differences

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--- aerocom:faq_aerocom [2015-04-22 17:41:13]
michaels
+++ aerocom:faq_aerocom [2022-05-31 09:29:31] (current)
@@ Line 1: / Line 1: @@
+ATTENTION - THIS WIKI PAGE IS NO LONGER UPDATED - PLEASE GO TO [[http://aerocom.met.no/|aerocom.met.no]]FOR LATEST INFO
 ====== Frequently asked questions AeroCom Web Interface ======
@@ Line 56: / Line 58: @@
 ==== Difference to reference version? ====
-DIFFMAP plots are available for some parameters.
+DIFFMAP plots are available for some parameters. They show the difference in percent to a reference field as map.
-==== Display two model versions ====
+==== Display and compare two model/data versions ====
-using two panels, use "synchronise panels" button to see corresponding images
+Use two panels, use "synchronise panels" to see corresponding images
 [[http://aerocom.met.no/cgi-bin/aerocom/surfobs_annualrs.pl?PROJECT=EMEP&MODELLIST=EMEP_SVN_TEST&FULL=2abbrev&Choice=&Type0=HISTO&Run0=EMEP_svn2892_141119DS_no2fac&Parameter0=SCONC_HNO3&Station0=EUROPE&Year0=an2008&Period0=mALLYEARdaily&Ref0=EBAS&Parameter1=SCONC_NH3&Station1=EUROPE&Period1=mALLYEARdaily&Type1=HISTO&Ref1=EBAS&Run1=EMEP_svn2892_141119DS_RG&Year1=an2008&PERFORMANCE=syn&INFO=hover&ChoiceMode=&STATE=7&|Example]]
+(note: the year is not changed on the second panel, so that this setting can also be used to compare different years)
 ==== Meaning of the variables ====
-Long description is visible by hovering over menu ite, and - if the info text (appearing above image when hovering over image) is not hidden
+A long description is visible by hovering over the Parameter menu item, and - in the info text (appearing above image when hovering over image)
 [[http://aerocom.met.no/cgi-bin/aerocom/surfobs_annualrs.pl?PROJECT=EMEP&MODELLIST=EMEP_SVN_TEST&FULL=explicit&Choice=&Type0=STATMAP-BIAS&Run0=EMEP_svn2892_141119DS_no2fac&Parameter0=SCONC_NO2&Station0=EUROPE&Year0=an2008&Period0=mALLYEAR&Ref0=EBAS&PERFORMANCE=ind&INFO=hover&ChoiceMode=&STATE=4&|Example]]
-==== Missing variable? ====
+==== Missing variable for a given model/data? ====
-Not all variables  make it sometimes into the AeroCom catalogue. If you have specific idea or request, send email to Michael with variable name.
+Not all variables  make it by default into the AeroCom catalogue. If you have specific idea or request, send email to Michael with variable name.
 ==== 3D diagnostics? ====
-not yet implemented in standard AeroCom.  To save space, ideally monthly 3D mixing ratios and profiles @stations (see HTAP-2 format and station list) can be output by the model. Ozone sondes and CALIOP profiles are candidates for near future standard diagnostics.
+Ozone sonde and vertical extinction profiles are now implemented in AeroCom. Filter models on variables VMR3D_O3 AND EC5323D_AER: [[http://aerocom.met.no/cgi-bin/aerocom/surfobs_annualrs.pl?PROJECT=EMEP&MODELLIST=EMEP_SVN_TEST&FULL=explicit&INFO=nohover&PERFORMANCE=ind&YEARFILTER=ALLYEARS&PSFILTER=EC5323D_AER&Type0=PROFILE&Ref0=EARLINET&Run0=EMEP_svn2982_150422ST_Trend&Parameter0=EC5323D_AER&Station0=BucharestRomania&Year0=an2012&Period0=mDJF|Example]]
 ==== Which year is used? ====
-The year in the menu refers to the observations year used and generally to the meteorology of that year. Year may be different in the model wrt to emissions.  Also a model simulation of year x maybe be compared to year y in observations. A different year for the model shows up in eg y-axis of SCATTERLOG file. Note that 9999 is used for a climatology for either model or observations, typically comprising 5-10 years.
+The year in the menu refers to the year of observation used. Note that anCLIM (or 9999) is used to point to a climatology for either model or observations, typically comprising 5-10 years. The meaning of the "year" may be more complicated for model data, because meteorology or emissions may come from another year.  Thus a model simulation of year x maybe be compared to year y in observations. Eventually the reference item contains than also the reference year. [[http://aerocom.met.no/cgi-bin/aerocom/surfobs_annualrs.pl?PROJECT=ACTRIS&MODELLIST=VERTICAL-PROFILING&FULL=explicit&INFO=nohover&PERFORMANCE=ind&YEARFILTER=ALLYEARS&PSFILTER=ALLVARS&Type0=PROFILE&Ref0=EARLINET_9999&Run0=EMEPglob.v2801&Parameter0=EC5323D_AER&Station0=CorkIreland&Year0=an2012&Period0=mJJA|Example]]
+A different year for the observation and model shows up also in eg x and y-axis of SCATTERLOG plot.
@@ Line 88: / Line 93: @@
 Versions can be removed from website, but that requires email to Jan & Michael.
-==== What means RMSspatial/temporal? ====
+==== Definition of Statistics used in Score tables and in Scatter plots ====
-For daily data analysis, RMS is split into the "spatial" RMS, calculated from monthly/seasonal/yearly averages and the "temporal" RMS, which is the residual (RMS^2temp=RMS^2-RMS^2spatial)
+Explanation for abbreviations used on scatter plots and in score tables:
+"#": Number of "observations" used for statistics (eg daily, monthly or yearly values)
+"#st": Number of sites
+"Obs": Observational mean constructed from all values in scatter plot (e.g. means from yearly station means are different from all daily value means : [[http://aerocom.met.no/cgi-bin/aerocom/surfobs_annualrs.pl?PROJECT=cci-Aerosol&MODELLIST=CCI-AEROSOL-products&FULL=2abbrev&INFO=nohover&PERFORMANCE=ind&YEARFILTER=ALLYEARS&PSFILTER=ALLVARS&Type0=SCATTERLOG&Ref0=AERONETSun2.0&Run0=AATSR_SU_v4.2&Parameter0=OD550_AER&Station0=WORLD&Year0=an2002&Period0=YEARLY&Type1=SCATTERLOG&Ref1=AERONETSun2.0&Run1=AATSR_SU_v4.2&Parameter1=OD550_AER&Station1=WORLD&Year1=an2002&Period1=mALLYEARdaily|Example]])
+"Mod": Model/Dataset mean constructed from all values in scatter plot, eg correspond to "Obs" values consistently.
+"NMB": Normalized mean bias, = (Mod-Obs)/Obs
+"RMS": Root Mean Square Error: SQRT(Sum( (y'-x')^2)/#)
+"R": Pearson Correlation Coefficient
+"RMSbc": Bias corrected RMS: SQRT(Sum( (ybc'-x')^2)/#) ; ybc' contains all model/data values corrected for the NMB bias. ybc=y*(Sum(x)/Sum(y))
+"RMSspatial": RMS from yearly mean station vales in observations and models. Model values consistently chosen for times when observations are available.
+"RMStemporal": Residual RMS after subtracting RMSspatial from RMS ( RMStemporal = SQRT( RMS^2 - RMSspatial^2 ), assuming error propagation and no covariance in temporal and spatial fields)
+...additional statistics in score tables
+"Spearman Rank Correlation": https://en.wikipedia.org/wiki/Spearman%27s_rank_correlation_coefficient
+"Spatial yearly Mean Corr Coeff": Pearson correlation coefficient from yearly mean values
+"Seasonal Anomaly Corr Coeff": Correlation coefficient of local anomalies wrt to annual mean.
+"Slope fit forced through zero": Regression of model on obs data, slope
+"Regression coefficient": Regression of model on obs data, regression
+"Regression constant, offset": Y intercept
+"STDDEV(Model)/STDDEV(Data)". Ratio of standard deviations
+"Score (mean relative bias )": sum(abs(tm-td))/# [ tm= model values, td= obs values ]
+"Taylor score": 4*(1+r)/((1+0.9)*(sm/sd+sd/sm)*(sm/sd+sd/sm) ) [ sm= Stddev of model, sd=Stddev of observations ]
 ==== Known bugs/problems/wishes ====
 -mountain sites are compared from surface level model output, use relative height\\