Calculate proportion of total precipitation received in the summer (June-August) needed for new wildlfire cheatgrass cycle implementation

[kpalmqui]

The proportion of total precipitation received in the summer (June-August) needs to be calculated and stored for use in the new wildfire cheatgrass cycle implementation.

precipitation that occurs in June, July, August / total annual precipitation

Should range between 0 and 1.

See SXW->ppt_monthly (monthly precipitation) & SXW->ppt (total annual precipitation)

[mnovo323]

Per our meeting: we will implement a function in ST_environs that will take a array of integers that represent months (0 = January, 11 = December), and calculate the proportion of precipitation of those months over the whole year.

[kpalmqui]

An update here: for all climate variables used in the calculation of wildfire probability (proportion of total precipitation received in the summer, mean annual temperature, and annual precipitation), we want these to be based on 10-year running averages, not this year's annual values. get_running_mean is likely to be helpful here.

[mnovo323]

Proposed changes:

---

Add a structure in ST_mortality.h to keep track of the past 10 years of the given data, and their average.

• structure named WildfireClimate which holds 3 arrays that hold 10 values, and 3 doubles that hold the average.

typedef struct WildfireClimate_st {
  double propSummerPrecip[10];
  double propSummerPrecipAvg;
  ...
  int count;
} WildfireClimate;

Add method to add the current years value, which will automatically update the structure and compute the new 10 year averages.

• the function get_running_mean() in generic.c in the soilwatt source code calculates a cumulative running mean rather than a simple moving average (average of past n values).
• To calculate the simple moving average we need to keep track of the oldest value in the array
  • If we increment the count every time we add new data to the arrays, then the location of the oldest values is count % 10.

Add initialization method.

• initialization method will allocate memory for the structure if it is not already allocated, and set all members to 0
• ST_mortality.c will keep a local pointer to a struct of this kind and will use that struct for all calculations.
  • in ST_mortality.c have WildfireClimate *wildfireClimate;

  • _getWildfireProbability() will access this local value by using the update function and getting the members by wildfireClimate->propSummerPrecipAvg

    Change the main functions to accommodate these changes

• Change ST_main.c to initialize this struct using the initialization method in ST_mortality.c
• Add methods to change the pointer in ST_mortality.c (getter and setter)
• Change ST_grid.c and ST_grid.h to have each cell keep track of their own

[kpalmqui]

Resolved by https://github.com/DrylandEcology/STEPWAT2/commit/1b60be281ebfbd19370ee64a91a64392771d8f9c