Twice a day both will be at about the same temperature and will provide no contrast to IR sensors. .  Wavelength  dependence  -  Each  of  these  loss phenomena is dependent upon wavelength. Sensors operating in certain bands have markedly different characteristics.  Remember,  the  compromise  is  usually between better resolution and less susceptibility to atmospheric  phenomena.    While  resolution  increases with  decreasing  wavelength,  so  does  weather sensitivity.  Table  10-2  shows  how  environmental elements  affect  wavelengths. .  Lessons  learned  from  the  field — Battle  experience  in  desert  areas  has  shown that the operation of optical instruments suffers  greatly  in  these  environments.  Rapid changes  in  the  index  of  refraction  can result in the shimmering of images, causing optical  instruments  to  lose  lock-on  tracked targets. — Mirages and other refractive phenomena also add to the confusion. — Frequent  airborne  haze,  dust,  sand,  and smoke   from   both   naturally   occurring winds and storms, and horn the battle, can hamper guidance or surveillance systems operating in, at, or near optical wavelengths. The  effects  are  more  severe  at  these wavelengths than at microwave, UHF, or VHF. WEAX AND AVWX LEARNING   OBJECTIVES:   Familiarize yourself with the procedures for obtaining route weather  forecast  (WEAX)  or  aviation  route weather  forecast  (AVWX)  support.  Recognize the  standard  format  of  the  two  products. Consider  the  obstacles  a  ship  underway  in  the Pacific in July may have to overcome. The CO feels uneasy; it is tropical storm season and there isn’t a weather division on board. Knowledge of this subject area may help the CO accomplish a successful mission. WEAX or AVWX information is useful to ships receiving OTSR support as well as for independent steaming units, since the OTSR service does not include specifically   tailored   weather   forecasts.   WEAX forecasts  are  designed  for  ships  without  embarked aviation units, while AVWX is tailored for ships with an embarked  aviation  unit. PROCEDURES WEAX/AVWX support services are requested in the movement report (MOVREP) in accordance with NWP  10-1-10.  Once  WEAX/AVWX  has  been requested on the initial MOVREP, units should continue entering the WEAX/AVWX notation to any subsequent MOVREP to ensure support is continued. Table 10-2.-How Environmental Elements Affect Wavelengths WEATHER  PARAMETERS Visible  and Near  IR Shortwave  IR Midwave  IR Longwave  IR Millimeterwave Low  Visibility severe moderate low low none Rain/Snow moderate moderate moderate moderate moderate/low High  Humidity low low moderate moderate low/none Fog/Clouds severe severe moderate/severe moderate/severe moderate/low Phosphorous/Dust severe severe/moderate moderate moderate/low low/none Fog Oil/Smoke severe moderate low low none 10-7