# Rainfall Standard of Disaster Prediction for Agricultural Droughs in S. Korea
## 3 Results
### Setting Up Rainfall in View of Disaster Reduction Relevant to Agricultural Droughts  
South Korea has four seasons, and about 65% of annual average rainfall occurs in summer. Most agricultural droughts occur before the monsoon season in summer, and droughts are reduced based on this. Since the start or end of an agricultural drought cannot be accurately determined, we want to analyze the rainfall before and after a month based on the time when the drought ends in the past data. Rainfall for reduction disasters in agricultural drought was analyzed for local governments and the whole country average monthly rainfall before and after a month based on the end date of the past agricultural drought damage. It analyzes municipality and the whole country and calculates monthly rainfall for disaster reduction to propose an integrated standard. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Year**} & **Agricultural Drought Damage Rainfall** & **Average Rainfall** & \multirow{2}{*}{**2)–1)**} \\  & **(mm)** & **(mm)** & **2)–1)** \\ \hline
1965 & 1115 & 1203 & 88 \\
1966 & 1117 & 1205 & 88 \\
1967 & 1119 & 1208 & 89 \\
1968 & 1121 & 121  
+++ ==WARNING: Truncated because of repetitions==
0 & 89 \\  
++  
The rainfall for disaster reduction of municipality was analyzed for total average rainfall of monthly rainfall about a month before and after the end of the agricultural drought damage (Figure 9). The average monthly rainfall for the month preceding the days when the agricultural drought damage ended by municipality was 164 mm (min 42 mm-max 311 mm). The average monthly rainfall for the month following the days when the damage ended was 140 mm (min 22 mm-max 239 mm). It was analyzed that the average rainfall before and after the month to disaster reduction of agricultural drought damage to all municipality is required. Monthly rainfall was analyzed about a month before and after the end date of the agricultural drought damage, by year, to reduce disasters for the whole country (Figure 10). The average monthly rainfall for the month preceding the day when the agricultural drought damage ended was 166 mm (min 67 mm-max 447 mm) per year. The average monthly rainfall for the month following the day when the agricultural drought damage ended was 131 mm (min 20 mm-max 393 mm) per year. Figure 10: Setting up rainfall for disaster reduction relevant to agricultural droughts by year. Figure 9: Setting up rainfall for disaster reduction relevant to agricultural droughts by municipality. Rainfall characteristics were reviewed through a linear regression analysis on the monthly average rainfall before and after a month for agricultural drought damage across the country. The monthly rainfall estimation equation for disaster reduction of agricultural drought damage in the whole country, using linear regression analysis, was determined to be \(R_{ddrr}=-1255+0.71\)Y. Here, Y is the year, and Radrr is the average monthly rainfall for disaster reduction of agricultural drought damage. Monthly rainfall for disaster reduction of agricultural drought damage, using linear regression, was analyzed (Table 6). The analysis of the disaster-reduction rainfall, using linear regression for ending the agricultural droughts by year, indicated that approximately 154 mm or more rainfall was required to end the agricultural droughts. The rainfall for ending the agricultural droughts averaged 154 mm (min 140 mm-max 178 mm). In this section, monthly rainfall in the month before and after the end of the agricultural drought was analyzed for municipality and the whole country for disaster reduction of agricultural drought. The monthly rainfall for solving agricultural drought by municipality was determined to be 152 mm as the average monthly rainfall for total municipality. The linear regression equation was calculated for monthly rainfall for the whole country to overcome agricultural drought, and 154 mm was determined based on past agricultural drought.