Updated image driver forcings and image driver global file

[yixinmao]

• Changed image driver VP from specific humidity (kg/kg) to kPa, and variable name from shum to vp
• Fixed incorrect unit attribute of air pressure (K to Pa) (issue Pressure units attribute in Stehekin image driver sample forcing are incorrect  #9 )
• Update the image driver global parameter file template to 1) be consistent with VP variable name change; 2) be consistent with global options of the classic driver template

[jhamman]

@yixinmao - can you post the output from ncdump below for the record.

[yixinmao]

Output from ncdump -h:

netcdf Stehekin_image_test.forcings_10days.1949 {                                  
dimensions:                                                                        
        time = 240 ;                                                               
        lon = 5 ;                                                                  
        lat = 4 ;                                                                  
variables:                                                                         
        int time(time) ;                                                           
                time:units = "hours since 1949-01-01" ;                            
                time:calendar = "proleptic_gregorian" ;                            
        double lon(lon) ;                                                          
                lon:standard_name = "longitude" ;                                  
                lon:long_name = "longitude of grid cell center" ;                  
                lon:units = "degrees_east" ;                                       
                lon:axis = "X" ;                                                   
        double lat(lat) ;                                                          
                lat:standard_name = "latitude" ;                                   
                lat:long_name = "latitude of grid cell center" ;                   
                lat:units = "degrees_north" ;                                      
                lat:axis = "Y" ;                                                   
        double mask(lat, lon) ;                                                    
                mask:_FillValue = 0. ;                                             
                mask:comment = "0 value indicates cell is not active" ;            
                mask:long_name = "fraction of grid cell that is activedomain mask" ;
                mask:note = "unitlessunitless" ;                                    
        float prcp(time, lat, lon) ;                                                
                prcp:_FillValue = 9.96921e+36f ;                                    
                prcp:long_name = "PREC" ;                                           
                prcp:column = 0 ;                                                   
                prcp:units = "kg m-2 s-1" ;                                         
                prcp:description = "PREC" ;                                         
        float tas(time, lat, lon) ;                                                 
                tas:_FillValue = 9.96921e+36f ;                                     
                tas:long_name = "AIR_TEMP" ;                                        
                tas:column = 1 ;                                                    
                tas:units = "K" ;                                                   
                tas:description = "AIR_TEMP" ;                                      
        float dswrf(time, lat, lon) ;                                               
                dswrf:_FillValue = 9.96921e+36f ;                                   
                dswrf:long_name = "SWDOWN" ;                                        
                dswrf:column = 2 ;                                                  
                dswrf:units = "W/m2" ;                                              
                dswrf:description = "SWDOWN" ;                                      
        float dlwrf(time, lat, lon) ;                                               
                dlwrf:_FillValue = 9.96921e+36f ;                                   
                dlwrf:long_name = "LWDOWN" ;                                        
                dlwrf:column = 3 ;                                                  
                dlwrf:units = "W/m2" ;                                              
                dlwrf:description = "LWDOWN" ;                                      
        float pres(time, lat, lon) ;                                                
                pres:_FillValue = 9.96921e+36f ;                                    
                pres:long_name = "PRESSURE" ;                                       
                pres:column = 5 ;                                                   
                pres:units = "Pa" ;                                                 
                pres:description = "PRESSURE" ;                                     
        float vp(time, lat, lon) ;
                vp:_FillValue = 9.96921e+36f ;
                vp:long_name = "VP" ;
                vp:column = 6 ;
                vp:units = "kPa" ;
                vp:description = "VP" ;
        float wind(time, lat, lon) ;
                wind:_FillValue = 9.96921e+36f ;
                wind:long_name = "WIND" ;
                wind:column = 7 ;
                wind:units = "m/s" ;
                wind:description = "WIND" ;

// global attributes:
                :title = "Stehekin 10-day example (19490101-19490110)" ;
                :history = "Created: Fri May  6 09:34:06 2016 by ymao" ;
                :institution = "University of Washington" ;
                :source = "/home/ymao/.conda/envs/vic5/bin/vic_utils" ;
                :references = "Primary Historical Reference for VIC: Liang,X., D. P. Lettenmaier, E. F. Wood, and S. J. Burges,1994: A Simple hydrologically Based Model of LandSurface Water and Energy Fluxes for GSMs, J. Geophys.Res., 99(D7), 14,415-14,428." ;
                :comment = "Output from the Variable Infiltration Capacity(VIC) Macroscale Hydrologic Model" ;
                :conventions = "CF-1.6" ;
                :hostname = "compute-0-2.local" ;
                :username = "ymao" ;
                :version = "VIC.4.2.b" ;
                :grid = "BPA Grid" ;
}