About the difference between the two surface data

[lby]

hello I found these two files surfdata_0.9x1.25_hist_78pfts_CMIP6_simyr1850_c190214.nc and surfdata_0.9x1.25_hist_78pfts_CMIP6_simyr2000_c1 in the surface data 90214.nc. However, I did the difference between their consent attributes and found that the data of the two files were exactly the same (the difference was 0), because simyr1850 and simyr2000 can represent the surface conditions of 1850 and 2000 respectively, so why are there no differences between the two data? How do they differ?

 

[oleson]

There are number of fields that are different in the two datasets, e.g.,

PCT_NATVEG
PCT_CROP
PCT_NAT_PFT
PCT_CFT
CONST_HARVEST_VH1
CONST_HARVEST_VH2
CONST_HARVEST_SH1
CONST_HARVEST_SH2
CONST_HARVEST_SH3
CONST_FERTNITRO_CFT

 

[lby]

There are number of fields that are different in the two datasets, e.g.,

PCT_NATVEG
PCT_CROP
PCT_NAT_PFT
PCT_CFT
CONST_HARVEST_VH1
CONST_HARVEST_VH2
CONST_HARVEST_SH1
CONST_HARVEST_SH2
CONST_HARVEST_SH3
CONST_FERTNITRO_CFT

Thank you for that answer, oleson. I have one more question. I want to use simulation to simulate an albedo change test. simyr1850 and simyr2000 used in the model have no change in the albedo attribute, so do I use simyr1850 and simyr2000 to do the control test with the same effect? Why would they be different if they weren't?

 

[oleson]

Are you talking about the urban albedo variables? If so, you are correct, the urban properties don't change between 1850 and 2000. If you want to do a test to see the effects of an albedo change, then you could run two simulations (e.g., both using an I2000 compset), one a control where albedo is specified by the simyr2000 dataset and one where you change the albedo values.

 

[lby]

Are you talking about the urban albedo variables? If so, you are correct, the urban properties don't change between 1850 and 2000. If you want to do a test to see the effects of an albedo change, then you could run two simulations (e.g., both using an I2000 compset), one a control where albedo is specified by the simyr2000 dataset and one where you change the albedo values.

Thank you for your prompt response, oleson. Yes, I said urban albedo, but I only found roof albedo in the surface data. What data should urban albedo be in? You mean using l2000compset, but doesn't the l test represent a test of some properties of the fixed land module? Is the surface data that I need to change for my experiment not suitable for my experiment? I don't quite understand this, I hope to get your answer!

 

[oleson]

There are other urban surface albedos on those files:

double ALB_IMPROAD_DIR(numrad, numurbl, lsmlat, lsmlon) ;
ALB_IMPROAD_DIR:long_name = "direct albedo of impervious road" ;
ALB_IMPROAD_DIR:units = "unitless" ;
double ALB_IMPROAD_DIF(numrad, numurbl, lsmlat, lsmlon) ;
ALB_IMPROAD_DIF:long_name = "diffuse albedo of impervious road" ;
ALB_IMPROAD_DIF:units = "unitless" ;
double ALB_PERROAD_DIR(numrad, numurbl, lsmlat, lsmlon) ;
ALB_PERROAD_DIR:long_name = "direct albedo of pervious road" ;
ALB_PERROAD_DIR:units = "unitless" ;
double ALB_PERROAD_DIF(numrad, numurbl, lsmlat, lsmlon) ;
ALB_PERROAD_DIF:long_name = "diffuse albedo of pervious road" ;
ALB_PERROAD_DIF:units = "unitless" ;
double ALB_ROOF_DIR(numrad, numurbl, lsmlat, lsmlon) ;
ALB_ROOF_DIR:long_name = "direct albedo of roof" ;
ALB_ROOF_DIR:units = "unitless" ;
double ALB_ROOF_DIF(numrad, numurbl, lsmlat, lsmlon) ;
ALB_ROOF_DIF:long_name = "diffuse albedo of roof" ;
ALB_ROOF_DIF:units = "unitless" ;
double ALB_WALL_DIR(numrad, numurbl, lsmlat, lsmlon) ;
ALB_WALL_DIR:long_name = "direct albedo of wall" ;
ALB_WALL_DIR:units = "unitless" ;
double ALB_WALL_DIF(numrad, numurbl, lsmlat, lsmlon) ;
ALB_WALL_DIF:long_name = "diffuse albedo of wall" ;
ALB_WALL_DIF:units = "unitless" ;

 

[lby]

There are other urban surface albedos on those files:

double ALB_IMPROAD_DIR(numrad, numurbl, lsmlat, lsmlon) ;
ALB_IMPROAD_DIR:long_name = "direct albedo of impervious road" ;
ALB_IMPROAD_DIR:units = "unitless" ;
double ALB_IMPROAD_DIF(numrad, numurbl, lsmlat, lsmlon) ;
ALB_IMPROAD_DIF:long_name = "diffuse albedo of impervious road" ;
ALB_IMPROAD_DIF:units = "unitless" ;
double ALB_PERROAD_DIR(numrad, numurbl, lsmlat, lsmlon) ;
ALB_PERROAD_DIR:long_name = "direct albedo of pervious road" ;
ALB_PERROAD_DIR:units = "unitless" ;
double ALB_PERROAD_DIF(numrad, numurbl, lsmlat, lsmlon) ;
ALB_PERROAD_DIF:long_name = "diffuse albedo of pervious road" ;
ALB_PERROAD_DIF:units = "unitless" ;
double ALB_ROOF_DIR(numrad, numurbl, lsmlat, lsmlon) ;
ALB_ROOF_DIR:long_name = "direct albedo of roof" ;
ALB_ROOF_DIR:units = "unitless" ;
double ALB_ROOF_DIF(numrad, numurbl, lsmlat, lsmlon) ;
ALB_ROOF_DIF:long_name = "diffuse albedo of roof" ;
ALB_ROOF_DIF:units = "unitless" ;
double ALB_WALL_DIR(numrad, numurbl, lsmlat, lsmlon) ;
ALB_WALL_DIR:long_name = "direct albedo of wall" ;
ALB_WALL_DIR:units = "unitless" ;
double ALB_WALL_DIF(numrad, numurbl, lsmlat, lsmlon) ;
ALB_WALL_DIF:long_name = "diffuse albedo of wall" ;
ALB_WALL_DIF:units = "unitless" ;

Thank you for your answer, oleson. I have another question. What you meant before is to use l2000compset, but does l test not mean the test of some attributes of the fixed land module? Is the surface data that needs to be changed for my experiment not suitable for my experiment? I don't quite understand, hope to get your answer!