what three forms of ice are present at the triple point marked o
Triple point The single combination of pressure and temperature at which liquid water, solid ice, and water vapor can coexist in a stable equilibrium occurs at exactly 273.16 K (0.01 °C; 32.02 °F) and a partial vapor pressure of 611.657 pascals (6.11657 mbar; 0.00603659 atm).[4][5] At that point, it is possible to change all of the substance to ice, water, or vapor by making arbitrarily small changes in pressure and temperature. Even if the total pressure of a system is well above the triple point of water, provided that the partial pressure of the water vapor is 611.657 pascals, then the system can still be brought to the triple point of water. Strictly speaking, the surfaces separating the different phases should also be perfectly flat, to negate the effects of surface tension.
Cirrus cloud Cirrus clouds are formed when water vapor undergoes deposition at high altitudes where the atmospheric pressure ranges from 600 mbar at 4,000 m (13,000 ft) above sea level to 200 mbar at 12,000 m (39,000 ft) above sea level.[13] These conditions commonly occur at the leading edge of a warm front.[14] Because humidity is low at such high altitudes, this genus-type tends to be very thin.[2] Cirrus clouds are composed of ice crystals that originate from the freezing of super cooled water droplets in regions where air temperature is lower than -20 °C or -30 °C.Cirrus usually occur in fair weather.They are formed when it is high enough to be cold and freeze the water drops into ice. They sometimes may be caused by turbulence and wind shear, or by upper-tropospheric convection. Sometimes they are like blown out ice-crystals spreading from the top of a dying cumulonimbus.