Monday, November 15, 2010

Nov. 15 - Time to wake up this blog after a busy summer getting the project started. Nice start to a fall windy season with some brief high PM10 around the border region. In Las Cruces we had high PM10 on evening of Friday Nov 12, Saturday afternoon, and again today. Winds were not high on the 12 and 13th so not sure about the cause. Today was a mix of clouds, sun, winds, brief showers, sun, and repeat. The day started off partly cloudy with NMSU campus temperatures at the freezing mark. Northwest winds dominated the day and started off breezy after 10 am. Noticed a lot of virga and low clouds right around noon and helped bring in winds on top of the upper level short wave. No thunderstorms in Las Cruces but brief showers felt like the summer. Intense downdrafts did a number around noon to 1 pm with lots of blowing dust at the NMSU campus. The picture below was taken right during the episode at 12:59 pm.

Clouds covered the area so satellites will not be useful for this event as the afternoon MODIS Aqua image below shows.

Nothing real exciting on the EPZ radar except spotty rain going NW to SE. Core site at the NMSU farm saw the event but not that spectacular.
PM2.5 tape ran out yesterday evening and forgot to load a new one in time for this event. Made a note to myself to check often. Started up PM2.5 BAM around 2pm. The morning PM10 concentrations shows a little more particulate matter than I expected. The graph below shows data from the MetOne particle sizer located on the NMSU campus. The red line is the coarse 10 µm particle counts (counts per cubic meter) and the blue is the 0.5 µm counts. Peak counts for both particle sizes occurred at 1 pm corresponding to the high wind and blowing dust event. In the morning from 7 to 9 am before the high wind event the smaller particles are seen at higher numbers than after 10 am. I would expect that we see aerosols during this calm period to be mainly locally generated particles from traffic, road dust, home heating, and maybe some burning. My guess is that after 10 am wind blown dust was the dominant type particle. Based on this plot we can see the clear differences between wind blown dust and the urban particles.

The NMED Deming airport site also showed a high wind event in the morning and into mid-day. Graph below is from the NMED AQB website.

Based on the radar wind profiler south of Deming winds were high all morning deep in the atmosphere with 30 kt NW winds beginning in 08 UTC near the surface.

Got a call from a colleague about very high dust at Chaparral High School today. Based on what I heard they had dust coming into the school and some thought it was smoke. Here's the time series from the NMED AQB site at the Elementary School.

The blue line is the hourly PM10 and showed a peak at over 750 ug/m3 at 1 pm. Winds were from the northwest (red line) as in the rest of the area.

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