def _calc_b(w, aod700):
b1 = <NUM_LIT>*aod700**<NUM_LIT:2> + <NUM_LIT>*aod700 - <NUM_LIT><EOL>b0 = -<NUM_LIT>*aod700**<NUM_LIT:2> + <NUM_LIT>*aod700 + <NUM_LIT><EOL>b = b1 * np.log(w) + b0<EOL>return b<EOL>
Calculate the b coefficient.