One of climatologists’ predictors of whether or not we’re going to have a big monsoon is the date of onset. Early onset generally means a wetter monsoon.[1] We’ve got no crisp definition here in Albuquerque (and, in fact, the monsoon onset isn’t very crisp here), but in Tucson they’ve developed a very precise definition based on dewpoints. Their start was June 28, nearly a week early. Compare that to the onset since 2001, when they had a late start all five years and a lousy monsoon four out of five years. I’m comparing apples to organges by using the Tucson start date, because that isn’t the definition used in the paper I cite below. And the actual correlations between Tucson’s onset date and total monsoon rainfall, either there or here, are so weak as to render the above discussion irrelevant. So it’s not science, just blind optimism.

Last year we had a false start in late June, and then things dried up. But we’ve got rain in the forecast for the next week.

[1] Interannual Variability of the U.S. Summer Precipitation Regime with Emphasis on the Southwestern Monsoon, R. W. Higgins and K. C. Mo, Journal of Climate: Vol. 11, No. 10, pp. 2582–2606

Going through some papers on my desk, I ran across this quote scribbled on a piece of paper:

Many droughts will occur; many seasons in a long series will be fruitless; and it may be doubted whether, on the whole, agriculture will prove remunerative.

That’s John Wesley Powell describing life in what he called the Arid Region, the lands west of the 100th meridian where rainfall averages less than 20 inches (~51 cm) per year. Less than that and it’s tough to make a go of it without irrigation, but Powell understood back then that you have to think about more than the annual average. What matters, he realized early on, is not only the mean but the variability around that mean.

It’s difficult to view Powell through the lens of history. We in the western U.S. tend to see our own ideas reflected in his. For me, it’s easy to imagine him now looking at the bungle we’ve made of things and saying, “I told you so.” But he did. His Report on the Lands of the Arid Region is amazing. Bernard DeVoto called it “One of the most remarkable books ever written by an American.”

(The Library of Congress has put the whole thing on line, and William deBuys included lengthy excerpts, along with a great introductory essay, in his collection of Powell’s writings.)

Rio-Grande-after-rain

Originally uploaded by heinemanfleck.

My first visit to Albuquerque, at least the first that I remember, was some time in the mid-1970s. I was a teenager, and we stayed with friends in Dietz Farm, in a house in the shade of the cottonwoods that backed up on the ditch along the east side of the Rio Grande.

I remember towering afternoon thunderstorms. We didn’t get wet every day, but a day did not go by that you couldn’t see them somewhere nearby. I’ve been remembering that visit this week, as the rains make a valiant attempt at returning.

We’ve had rain in parts of New Mexico every day for the last week or so, spotty thunderstorms that have an awfully monsoonal look. The forecasters have been suggesting it’s not quite monsoonal yet, and I haven’t been doing of my own journalistic due diligence, so I’ve no ammunition with which to disagree. But whatever it is, it’s been lovely.

Yesterday morning I rode my bike up to the Alameda Bridge at the north end of town, and the river was running a beautiful muddy red. The river’s been quite low, but if you click through to the link you’ll see how it popped up every time it rained over the last week.

Continue reading ‘Monsoon Watching’ »

We got 0.41 inch (1 cm) from that one*, Mark.

That brings my rain gauge total to 0.93 inch (2.4 cm) for June. Also 0.93 for the last four days. That makes this the wettest month since October. The water year at my house:

• Oct. 1.94 inch (4.9 cm)
• Nov. 0.03 inch (0.1 cm)
• Dec. 0.15 inch (0.4 cm)
• Jan. 0.03 inch (0.1 cm)
• Feb. 0 inch (0 cm)
• Mar. 0.17 inch (0.4 cm)
• Apr. 0.13 inch (0.3 cm)
• May 0.2 inch (0.5 cm)

* For those who don’t live in my neighborhood, “that one” = storm cell that rolled through town in the early evening. It was a relatively small cell, but Mark and I happen to live right beneath it.

Back in January, there was a huge debate in the comments here about “flora gains” – the suggestion by one of the regular commenters that we’d benefit from enhanced carbon dioxide because the plants on which we depend for food etc. would do better, with CO2 fertilization more than making up for any negative effects from climate change. It was one of those classic blog comment shouting matches, mostly heat and not much light, and I pretty much stayed out of it.

There are a couple of papers in tomorrow’s Science that add some light, and they suggest that the case for CO2 fertilization benefits has been overstated.

The problem, outlined by Stephen Long of the University of Illinois and colleagues is that the “enclosure studies” supporting flora gains were not terribly realistic. With better technologies that have allowed testing of enhanced CO2 in real-world settings, the benefits are far smaller.

I don’t know enough about the issue to understand where this fits in the broad sweep of research on this question. But I do know that this is a fair piece more interesting and important than hockey sticks, as this is the sort of stuff we actually need to understand in order to figure out what to do.

Food for Thought: Lower-Than-Expected Crop Yield Stimulation with Rising CO2 Concentrations, Long et. al, Science 30 June 2006: Vol. 312. no. 5782, pp. 1918 – 1921, DOI:10.1126/science.1114722

Climate Change and Crop Yields: Beyond Cassandra, Schimel, Science 30 June 2006: Vol. 312. no. 5782, pp. 1889 – 1890, DOI: 10.1126/science.1129913