T h e te rra in flu c tu a tio n is o n e o f th e m o st im p o rta n t e r r o r so u rc e s of r a d a r o b se rv a tio n , w h ic h w ill c a u s e th e d a ta d is to r - tio n at a n d b e h in d th e o b se rv in g site o n th e r a d a r b e a m p a th . T h e s e c o n d —stag e N a tio n a l F lo o d C o n tro l a n d D ro u g h t R e lie f C o m - m a n d S y stem P ro je c t c o n s tru c te d w e a th e r r a d a r a p p lic a tio n sy ste m . A m e th o d for a n a ly z in g o b je c tiv e ly th e w e a th e r r a d a r sta tio n s c a n c a lc u la te a n d d is p la y th e b a rric a d e d e le v a tio n m a p , th e e q u iv a le n t b e a m ra n g e m a p at th e s a m e h e ig h t a n d th e b e a m b lo c k a g e c o - e ffic ie n t m a p . T h is p a p e r in tro d u c e d c o m p u tin g p r in c ip le s a n d m e th o d s fo r b a c k g ro u n d fie ld fe a tu re d a ta o f C IN R A D . A n a lg o rith m w as d e v e lo p e d to c o m p u te p ro b a b ility d istrib u tio n o f r a d a r e c h o . By c o m p a rin g a n d a n a ly z in g th e b a c k g ro u n d fie ld fe a tu r e d a ta a n d d iffe re n t e le v a tio n s ta tis tic a l p ro b a b ility d istrib u tio n o f ra d a r e c h o , it v e rifie d th e c o rre c tn e s s o f b a c k g ro u n d fie ld fe a tu r e d a ta o f C IN R A D . In th e n e x t s te p , w h ic h will p ro v id e th e b a s is for q u a n tita tiv e ly c o rre c tio n o f th e b e a m b lo c k a g e reg io n .