There is this saying: “Rain, rain, go away. Come again some other day.” There were times during my childhood that this saying would be recited – the times that I recited this myself and times when I heard others do likewise. Notice I said “recited.”
I haven’t heard this expression for a long time and probably for good reason. Rare it is these days in the American Southwest when there is rain. California is now in its fourth year of drought.
Rain is important in California: The precipitation that falls as snow in the Sierra Nevada Mountains supplies water to the Valley and the San Francisco Bay Area when the snow melts: area reservoirs’ supplies become replenished, ground water gets recharged through which there is the availability of water for drinking, bathing, washing clothes, irrigating farm crops, watering lawns, etc. Not having this precious resource, to put it bluntly, would be like being up the creek without a paddle.
![Fireplace_Burning[1]](https://i0.wp.com/alankandel.scienceblog.com/files/2012/12/Fireplace_Burning1.jpg)
Once again, at fault is that “Three-R” (ridiculously resilient ridge) weather pattern that, like last year at this same time, has parked itself over the U.S. southwest. High pressure is preventing any chance of rain from moving off of the Pacific Ocean and dumping that on the West’s semi-arid and arid landscape – which so desperately needs this. Might I mention also that the Midwest and Northeast are feeling the effects of another “Polar Vortex.” The southeast even isn’t being spared of winter’s chilling grip.
What I’m beginning to wonder is if this is going to become an annually recurring weather pattern. In “Blizzards, droughts, polar vortexes, other weather-related phenomena: So what gives?!” posted on Nov. 24, 2014 I inquired: “I ask: For what weather-wise this year exactly are we in store? A, excuse the expression, ‘carbon’-copy of last year’s ‘Triple-R’ (‘ridiculously resilient ridge’ or ‘RRR’) weather pattern if not more? My observation is this: conditions are playing out in the fall in this year in much the same way.”
It is rain that we need that we’re just not getting and wind added in, necessary to mix up the atmosphere enough to disperse pollutants that in some parts – like California’s San Francisco Bay Area and San Joaquin Valley regions – has become so concentrated in the air that it is unhealthful to breathe and which, unfortunately, has now stuck around for days and, in some cases, weeks. It is as if this pollution visible in our skies has come on with a vengeance.
To show just how bad the air has been this year so far, in the San Joaquin Valley, for particulate matter less than 2.5 micrometers in diameter (PM 2.5), every day since Jan. 1 there has been an exceedance. Measured in micrograms per cubic meter of air (ug/m3) and keeping in mind that the national 24-hour standard of health for PM 2.5 is 35 ug/m3, over the dozen days for which data is available, the low was 38.1 with a high of 99.3 ug/m3, the daily average being 67.025 ug/m3.
The Bay Area has similarly suffered, but not near as badly. Fine particulate matter exceedances were recorded on Jan. 3 (38.0 ug/m3), Jan. 6 (36.2 ug/m3) and Jan. 8 (41.4 ug/m3) or a daily average of 38.53 ug/m3. Notice the difference.
![320px-Los_Angeles_Basin_JPLLandsat[1]](https://i0.wp.com/alankandel.scienceblog.com/files/2012/12/320px-Los_Angeles_Basin_JPLLandsat1.jpg)
Meanwhile, the South Coast Air Basin (southern California), has fared somewhat worse in this regard than the Bay Area but so much better than the San Joaquin Valley.
Case in point: The South Coast Air Basin, in this same 12-day span, has had seven such exceedances. South Coast Air Basin exceedances have ranged from a low of 38.0 ug/m3 to a high of 62.0 ug/m3 with a daily PM 2.5 average of 47.13 ug/m3.
According to weather forecasters, a low-pressure cell is not expected to arrive in state until Monday of next week. What that means for the rest of this week and Sunday of next, is no break in the Valley’s inversion layer that is enabling the dirty air principally below 1,000 feet in elevation to persist.
Folks here particularly should not rely on meteorology only to filter and clean the air. Instead, Valley residents can play and take a greater role in helping to keep this toxic air from first building up and therefore not allow it to reach the concentrations it has.
Middle images (both): NASA
– Alan Kandel