I've been pondering arctic phase changes and etc for a while and kept getting confused by one thing...
If you have an ice floe or similar condition of both ice and liquid existing close to the freezing point, you also have water vapor existing, right? But as I understand the usual phase diagram, in normal conditions (e.g., ~100kpA/1ATM pressure) you should only have liquid and solid states, the triple point being much lower.
What am I missing?
What I ultimately want to know is the equation for the water vapor capacity of air vs temperature even well below 0C.
Another thing I've been pondering, and quite related, is where the extra heat goes as one approaches a state where the arctic is increasingly ice free (since it doesn't go into melting the ice any more). The sun shines on the water and it absorbs heat (in the summer). Presumably it loses heat to the atmosphere via evaporation, albeit at a much lower rate than would be the case in the tropics, but is this a meaningful number? And even if it is, where else can that heat go? I assume the extra longwave radiation is not that significant.
In other words, how much heat could be retained in the cryosphere season-to-season?