MODTRAN, The One ppm Exercise

MODTRAN is impressively nuanced sometimes. Ordinarily MODTRAN is used on a macro scale at plausible altitudes and greenhouse gas concentrations, but it definitely resolves at single meters of altitude and single ppm of greenhouse gasses.

Here we explore one ppm CO2 with all the other GHG’s zeroed out. We look both up and down from one meter, and 70 kilometers.

Modtran Up and Down 1 meter 1 ppm ann

Beginning at one meter, we see little difference from the Planck curve looking down. This is no different from what we see at 400 ppm looking down up to about 400 meters altitude, except that there is .31 W/m2 MORE upward radiation at 400 ppm.

Looking up from one meter the reach of a single ppm of CO2 is astonishing. The 667.4 fundamental bend does not quite kiss the downward looking curve, meaning that it is seen radiating from some small distance above one meter. Only the fundamental bend can be seen radiating from essentially the surface to an altitude of about six kilometers.

At the temperature of six kilometers the additional bending vibrations at 647.1 and 688.7 kick in, along with the P and R rotations dependent on the fundamental bend. At a temperature 15 kilometers we see the additional vibration at 618 and the bend to stretch transition at 720.8

Interestingly, at 1 ppm you get almost a “chromatograph” of the relative intensities, with the factor of progressive movement away from top dead center of the Planck curve with increasing altitude omitted.

Modtran up and down 1 ppm 70 km

The view of 1 ppm from 70 kilometers is I’m many ways the inverse of the view from one meter. Looking up from 70 km there is essentially no IR coming down from above. Looking down we see the “effective radiative levels” of the CO2 transitions to space. The fundamental bend at 667.4 is seen radiating at a temperature of 12 km, and once again it shows extraordinary reach, being the only signal from 6 to 12 kilometers.

At 1 ppm, there is essentially no difference in either upward or downward radiation above 25 km elevation.

Just for kicks, below is 1 meter looking up vs 70 km looking down at 1ppm.

One meter looking up vs 70 km looking down

Let’s compare the 1 meter up and down view at 400 ppm.

Looking down, there is no discernable difference from 1 ppm, and the total upward IR flux is only .31 W/m2 more at 400 ppm.

There are lots of differences looking up. The fundamental bend and rotations, and the nearby three order of magnitude weaker transition at 647.1, have melded into a zone radiating at the Plank temperature of the ground (299.7 K). Notably, this is above the temperature seen looking down. The upwelling radiation deviates from the Planck curve more at top dead center than elsewhere along the curve. The downwelling radiation is seen at a higher temperature at the ground BB curve.

The transitions at 618 and 688.7 radiate at about the upwelling (down looking) curve, 597.3 and 720.8 are seen radiating at the temperature of perhaps 800 meters, and a crop of extremely weak transitions is seen radiating above 9 kilometers.

Astonishingly, there is a 60.5 W/m2 increase of downward flux between 1 ppm and 400 ppm, as seen from one meter elevation.

Here is 400 ppm up and down from 70 km.

Up and Down 70 km annotated

We have the usual cast of transitions, but their intensities (and temperatures) change with altitude and CO2 concentration. The difference in upwelling radiation between 1 meter and 70 km is 118.75 W/m2 at 400 ppm.

A transition can be deemed “saturated” when it radiates at a temperature conforming to the Planck curve. At 400 ppm from 70 km, the fundamental bend rotations are radiating at the 220K (12 km) curve, but the 667.4 bend itself reaches back down to a temperature of 9 km.

For kicks again, 1 meter looking up vs 70 km looking down at 400 ppm.

One meter looking up vs 70 km looking down 400 ppm

 

The fundamental bend is saturated looking up from a meter, but not above 9 km in the atmosphere.

Advertisements
Posted in MODTRAN | Tagged | Leave a comment

Infinity and Things to Do.

Infinity is meaningless. Everything is nothing.

When you rise every morning, the possibilities are infinite.

The difference between everything and nothing is you.

Posted in Climate | Leave a comment

Alexa and Chatty Cathy

Chatty Cathy was a doll. You could pull this string on her and she would say something random. She was the first electronic fortune cookie. She could say  maybe a dozen and a half different things. Never anything cogent. Some tangy things to keep your interest, some sweet things to butter you up, but nothing to piss you off by design.

So it is with Alexa. Algorithm rather than string. Marketing to lonely people. A pretense that your voice phonons in a virtual world, in  conversation with a remote server, is real.

Handy, but not real. Handy as a voice activated search engine (there are others). Handy if you want to listen and nobody else wants to talk…

Posted in Human need for Judgdment, Sociology | Leave a comment

The Terribly Tenacious Trough

 

Humans are prone to emotional conclusions like “the weather has gone crazy”. Last year at this time, even with the normal rainfall in the north half of the state, many asserted that California was in “new normal” permanent drought. The far above normal rainfall throughout the state this year shows that this sentiment is clearly wrong, but the same folks who set forth permanent drought will now assert unprecedented “crazy rain”.

We have done a series of posts on the drought in California using data from San Francisco that dates back to 1850. Here we present a look at the same data looking at high rainfall years in the same data set to evaluate how crazy this year really is.

SF Cumulative 2016-17

Perhaps this year’s trough is not so terribly tenacious after all. The season is not over and the tingling in my own bones is that it will be a wet spring, like many I remember from the seventies. Nevertheless, if I were a betting man, I would bet that this year will top out below the five previous years shown. If this season dries out, there will be more years to add above this year.

The point here is that the “ridiculously resilient ridge” that led to four consecutive years of below normal rainfall in California did not produce any individual years of record drought. If the terribly tenacious trough does the same in reverse, where are we?

As we have always been; naked apes staring into the sunrise. Is God punishing us?

If you want to project your guilt onto statistical noise, you go.

I’m going with the data.

Posted in Climate | Leave a comment

Effective Radiative Level

There is this concept that by averaging all the different radiative spectra that satellites see from earth from very high altitudes an Effective Radiative Level can be derived that has meaning for the radiation balance for the planet.

The basic idea is that the addition of greenhouse gasses, predominantly CO2 by humans, will raise the Effective Radiative Level. The further idea is that this supposed increase in altitude for the radiative level takes place within the part of the atmosphere where there is lapse, i.e. the atmosphere cools with increasing altitude.

The claim is that since a higher altitude implies a cooler temperature, the radiation to space will take place at a lower blackbody temperature with lower energy to the fourth power, and will cool the planet less effectively.

We have developed the tools to evaluate this claim. Rather than a single average level and blackbody temperature, the satellites see substantial differences in radiative altitude across the earth longwave spectrum.

All Down Looking, Planck Bounding

The “effective” radiation seen from space in the earth long wave spectrum ranges about 100K, from a remarkably consistent  220+-7K for the CO2 bands to a wildly different 320K+ in the atmospheric window.

The bottom line is that CO2 has its own radiative channel to space entirely separate from the effective Planck temperature of the atmosphere as a whole. This channel radiates at the tropopause and above where the lapse rate reverses and becomes negative. Rather than radiating at a lower temperature, with increasing concentration and higher radiative altitude, CO2 radiates to space to the fourth power of a higher temperature with increasing concentration.

 

Posted in Climate | Leave a comment

The Apology of Chaos

One grows weary of the, “it’s a non-linear, chaotic system” apology for human failing to accurately model weather and climate. This idea seems to have stunted roots in the very different worlds of the Lorenz Butterfly, and quantum probability.

Never mind that the scales of these two worlds are wildly different, and what may be currently unknowable at quantum scale is definitely not unknowable at butterfly scale.

The logical extent of this conflation of concepts leads to the conclusion that by merely observing Lorenz’ butterfly, we disturb it and irretrievably alter the future.

In the real world the effect of a butterfly wing flap is as insignificant to weather and climate, as quantum wave function probability is to navigating to the moon.

Chaos becomes an apology, an excuse to throw up ones hands and declare the task impossible. The task of understanding weather and climate is not impossible. It is just very difficult.

Posted in Climate | Leave a comment

Alternate “Facts” and Science.

Every “fact” so far that we naked apes have ever believed we have known, has proven to be incorrect at some level.

The operative verb in the sentence above is “believe”.

Alternate facts discovered by inquisitive people challenge the existing system of belief.

Often, when there is no clear economic benefit from the challenging fact, the investigators are persecuted.

Human nature.

[metalogue]: Science is the business of discovering alternate facts.

Posted in Climate | Leave a comment