What I hope to accomplish with this thread is to create a "realistic" biome map of the Moon.
I have followed my own little muse which is enthusiastic about aeronautics and astronautics and space missions as soon as damn possible. The project here is biomes, which is why we are in the Map section I guess.
But I have remarked that perhaps, to keep the ambient temperature of Luna's daytime surface reasonable, we might actually want to minimize rather than maximize the greenhouse effect. Earth is certainly said to be in danger of runaway greenhouse effect. The way that works is, the amount of water vapor in the lower atmosphere depends to a great deal on the saturation humidity capacity of the air, which is strongly dependent on temperature. If the surface warms up significantly, more water can evaporate and be lofted up higher before the air parcel it is in cools enough to saturate and start releasing the vapor as condensed liquid or solid water--which forms clouds. Clouds reflect light but also absorb heat, as does water vapor in gas state. The more water, the more heat can be trapped, balanced perhaps by more clouds reflecting away more light. Combining that with a thicker atmosphere, that is six times as many cubic meters corresponding to six times the linear length at a given density range, and perhaps Lunar air humidity has to be kept rather low on the average to prevent a runaway greenhouse heating.
This might suggest that the average saturation of the lower atmosphere air must stay low, which implies pretty arid conditions on the surface--rather consistent with your map as it happens.
The effect on biomes is that broadly speaking, upwind from a given crater lake or small sea, the air is arid, and downwind the water that does evaporate will be diluted in lots of warm still fairly dry air. It has to precipitate somewhere to be sure!
Lo and behold--if the day side has very low precipitation, as air is lofted over to the night side it ought to cool and the water snows or hails out, and once fallen, if the surface temperatures drop below freezing, it largely stays put in drifts...until dawn comes and the surface starts to be warmed. Ice will melt and be liquid water at very low temperatures just a few degrees above freezing, and so might soak into the ground or be sequestered by organisms, plants tapping it out of the soil or animals drinking it. There might be a mad scramble in the ecosystem to sequester the water against the hot dry period of most of the near two week long day, with plants using stored water and atmospheric carbon dioxide along with minerals and other nutrients picked up during the brief period of some days where liquid water is in air cool enough yet not to absorb too much of it, to use the abundant day sunlight to synthesize food to sustain the plant during the long cold night. If nighttime temperatures are below freezing, some organisms like arctic frogs might allow themselves to be frozen and go into suspended animation, and jump start themselves with some triggered chemical reactions to melt the ice and use up stored nutrients to get active in the early dawn period to scramble for more water and food.
Now against this interesting idea of a dry dry arid daytime with plants and animals watered by night side snow, consider again the details of how air circulates. Say we have parcels of dry air over a large body of open water, being heated by the daytime sun. Dry air will tend to absorb water vapor, encouraging evaporation which will cool the sunlit surface. Then, the parcels will rise convectively, expanding as pressure drops and thus being cooled but also lowered in density. Even if only partially saturated with water vapor before convection lifts the parcel out of contact with the open water, as the parcels rise they will drop toward saturation; after this the dry adiabatic lapse rate is replaced by a wet adiabatic lapse rate, in which temperatures fall more slowly due to heat of vaporization being released as water condenses. This lofts the parcel up still higher. But eventually, long before the stratosphere is reached, clouds will form and precipitation will occur, over the day side. If the surface is hot enough, the precipitation will evaporate even before it hits the ground, but this will cool the layer that absorbs it--checking convection, or trapping convective air in an inversion.
Thus while the air initially picking up the water is lofted higher than ever due to releases of heat of vaporization, the water molecules themselves tend to be filtered out, dropping as precipitation to lower levels. At least some of the time, precipitation will reach the surface, and will be scattered far from its condensed surface pool sources.
If much water is trapped at a low level, when the Moon slowly rotates into night side conditions, recall I have argued the lower atmosphere tends to have a wind blowing from the cold dark side to the sunlit side. Such winds would tend to push the more saturated lower level layers back to the day side. But also, being quite chilled by the night side (I haven't worked out how cold the night side might be to be sure) we have basically a warm front over an advancing cold front. Clouds will form there, heat of vaporization be released, lofting the air parcels and causing precipitation along the cold front--which tends, on the evening terminator, to fall through the very chilly intruding cold front air and either be frozen as sleet before it hits, or fall as chilled liquid but quickly be frozen on the surface.
In the morning, surfaces that have cold soaked all night are being brought back into the day side, along with a flow of cold dry air running ahead of the planetary rotation to again form even more intrusive cold fronts under a warm saturated front--again causing storms and precipitation, but this time even if it does fall in frozen form, the rising sun tends to warm the surface and melt any ice.
So it is a little like the model I first offered--the water vapor evaporating over the course of the day from the small seas and lakes and ponds might precipitate down during the day or might be trapped up higher, but still in the lower troposphere atop inversions. At sunset, this water is chilled out of the air and falls to freeze on the surface (or be ingested by plants or animals preparing to hibernate for 2 weeks. Then at dawn, this load of ice atop the surface is supplemented by more precipitation and a general thaw, but again plants and animals ought to scramble to sequester it leaving the surface air rather desertified.
So--biome wise, on land, the air is arid and hot during the day. Clouds might form up high but not rain a lot down to actually water the surface; the lakes and seas will be shrinking all day. If the night side is deep chilled, well below freezing, the terminator storms will involve harsh clashing low dry cold fronts under lofted rainy warm fronts that might drop a lot of precipitation. After the sunset storms though, the chill predominates and weather calms down a lot--no sunlight to drive circulation beyond what is driven by dayside high altitude air pouring down. The middle days of the night cycle will be very calm; what clouds remain will be thin ice cirrus hazing the sky a bit.
Note a huge difference between Nearside and Farside of the Moon at night! On Farside, when it is night, the Moon lies beyond Earth relative to the Sun, Earth sees a full moon (Nearside all lit up) and Farside faces deep space. There is no illumination beyond the occasional lightning flash or fire (most likely near sunrise or sunset, by far) but the planets and stars. Venus would be sometimes visible low on the horizon as morning or evening star and the brightest object in the sky; Jupiter and Mars, and the brighter stars, will be the leading lights. Total illumination levels will be quite low, it is effectively pitch black. On Nearside on the contrary, when it is midnight and the chilled calm of the central disk as seen from Earth prevails, the Moon is new, and Nearside sees a full Earth beyond Luna relative to the Sun. Benford claims the Moon's albedo would be 5 times its current reflectivity, making full moon nights on Earth much brighter...but full Earth then will be some 80 times brighter than an OTL full moon. The cold Nearside night will be lit up pretty well; dim versus proper daylight but probably quite bright enough to see colors or read newsprint.
Broadly speaking this holds in any possible combination of day and night weather; clouds at night I think would be fairly thin even if humidity is a lot higher, since high altitude air pouring in from the day side is pretty well wrung out before it flows nightward. How cloudy the day side is is another story!
I suppose Benford's "Florida" rather than my offered dry air "New Mexico" Luna might be possible after all. If it is pretty hot and also wet on day side, then while air will take up a lot of humidity from evaporation over sea and land, it will also rain a lot. The surface might be maintained in a wet state, with excess water seeping into streams and feeding the lakes and seas to maintain their level despite heavy evaporation. Moisture would be well distributed--just as in "New Mexico" conditions, aridity prevails even near the water bodies.
Can the night side be kept so warm that even in the chilliest days before dawn, the temperature has in fact not dropped below 273 K, freezing, and water remains generally liquid? I suspect that would be too warm to allow for the circulation to maintain those temperatures unless the day side is quite sweltering, too hot for humans to live at all well in.
However, there is also the matter of latitude. At the equator, the day night cycle is as described, but what about the poles?
If we assume night temperatures do fall below freezing, at each pole, air is always flowing over the pole from the cold side, and being below freezing all precipitation from as yet untapped clouds that surge so far north or south will take the form of snow, hail, or ice storms. And the thaw never comes; the cold wind boxes the compass and it is always twilight, but the proper hot day never comes due to the low tilting of the Lunar axis relative to the norm of the ecliptic. Thus ice accumulates, and must form a permanent glacial ice cap. At whatever average rate precipitation does reach the poles, or the lower latitudes where the cold flow prevails to keep temperatures below freezing, that mass of water must in equilibrium be surging equatorward. Low Lunar gravity means that ice sheets too can be six times thicker than Earth's for similar flow pressures so quite a lot of water might be in the polar caps!
But at some latitude, the warm air of the day side must surge there often enough to warm the temperatures in mid day above freezing, and there the glacier will start to melt and feed daytime rivers flowing equatorward (if topography routes them poleward, they will just freeze again so these transition zone rivers pretty much have to flow to the tropics). As we go to lower latitudes, the period in which thaw happens and gives way to increasingly high temperature peaks in the "afternoon" days lengthens as the peak temperatures rise. So even if the tropics are in fact hotlands too hot and humid for humans to prosper in, there will be belts at moderate latitude where peak temperatures are bearable and the average temperature is much lower--because the entire night time is deep frozen and much of the dawn and late afternoon are also below freezing, and probably quite stormy too. But perhaps a week or more of decently warm, survivably calm weather might intervene, and glacial fed streams and rivers making their way to the basins will keep regional moisture at decent levels.
Eventually one comes to a latitude where perhaps peak temperature and humidity is downright deadly, and below those latitudes humans must either stay out or make elaborate shelters against the excessive to us heat. However I would expect local Lunar organisms to be well adapted and able to thrive and move about even if peak temperatures near the equator rise to 50 C or more. This would be a high humidity scenario to be sure.
Heat transport to the dark side probably cannot be so great as to maintain the dark side above freezing, but it might not drop a very far amount below freezing. After all if the ground is covered in snow, the emissivity of the surface is low; the oceans being small and perhaps covered with ice too. Between the Stefan-Boltzmann law meaning low surface temperatures correspond to very low black body emission rates, and the low emissivity of the surface, perhaps quite modest thermal fluxes from the day side can serve to maintain temperatures not drastically below 0 C.
The lower limit would be the temperatures at which oxygen starts to precipitate out; if that starts happening latent heat release should go a long way toward checking further temperature lowering, whereas it would also represent a drop in ambient pressure that would hustle in more dayside sourced upper atmosphere air and thus more heating. Intuitively with air 6 times thicker than Earth's and a planetary circumference 1/4 that of Earth, I doubt it could get that cold, and even wonder if it could get as cold as Terran polar regions ever do. Still there is a lot of room between that and freezing! A snowball dark side is what I would expect, unless the overall humidity is so low the snow is very patchy.
So these are my biome predictions then:
1) substantial and very thick permanent ice caps around the poles, with a surrounding tundra band of chill land that does thaw (on the surface, probably a lot of permafrost under the ground), giving over to fairly well watered taiga (even on a pretty dry moon--as noted, the water simply builds up in the polar zone, until it is thick enough to flow glacially and then as streams.
2) a) New Mexico Luna scenario: depending on how moist it is, either the zone beyond the glacial boundaries quickly dries off, living organisms have desperately sequestered the temporarily flowing water of dawn, and the air dries out, clouds recede very high in the sky and the surface bakes in Saharan or Empty Quarter aridity and heat. But unlike the Sahara or Empty Quarter, a fair amount of moisture was available and living organisms have sequestered it; those plants and animals are quite abundant despite the killing drought, for they are all adapted to fanatically hang on to that water and make the most of it. So, life grimly hangs on and tries to put the abundant solar energy to good use without shedding any water. Of course predation will accidentally release some moisture.
2) b)--if it can be shown that sufficient humidity will not drive tropical temperatures to killing extremes, or anyway that while that happens at low latitudes, bands of survivable peak temperatures will exist between the glaciers and this hot band, then we could have it a lot wetter and presumably greenhouse superheating will not happen. Then indeed the lower latitudes will resemble Florida, or even the Amazon rainforest, in the day.
But unless someone shows me the math I believe the entire night side must be below freezing, which means the poles are above freezing, and in a high humidity version the glacial caps are spreading rapidly, but trimmed aggressively at their edges by aggressively warm daytime temperatures. Even the ultra hot lands in a moderately high greenhouse hotbox for the middle of the day will be plunged into Arctic cold at night. Which of course means the flora and fauna will be quite different from those inhabiting tropical lands on Earth--they will in fact be much more like temperate zone critters.