| | 52 | |
| | 53 | Message de Karl Taylor sur la normalisationn des variables: |
| | 54 | All variables are considered to be in a "Category A" except the following Category B variables, which are either: |
| | 55 | |
| | 56 | - intensive in area and quantify the area of a particular type (e.g., sea_ice_area_fraction), or |
| | 57 | - extensive in area (e.g., sea_ice_volume, sea_ice_mass) |
| | 58 | |
| | 59 | The time mean of category A variable is calculated as follows: |
| | 60 | |
| | 61 | Amean = sum_over_time (f_n * H_n) / sum_over_time (f_n) |
| | 62 | |
| | 63 | where n is a time sample and f is the fraction of the cell where H exists. |
| | 64 | For category B: |
| | 65 | |
| | 66 | Bmean = sum_over_time H_n / N |
| | 67 | |
| | 68 | where N is the number of time samples. |
| | 69 | |
| | 70 | Note that when H exists over the entire grid cell (i.e., isn't restricted to a portion of the cell), f_n = 1, and Amean = Bmean. |
| | 71 | |
| | 72 | For the cases you mentioned in your email: |
| | 73 | |
| | 74 | albedo over snow-covered surface: we will need to confirm, but this would be a category B variable defined only over the portion of the cell with snow. |
| | 75 | |
| | 76 | LAI: Since it is an index it might be defined even over the ocean, but we need to check. |
| | 77 | |
| | 78 | |
