21 Nov
The data continues to show a rich variety of circulations and interactions not previously discussed in the literature, at least not in terms of anything concrete. I have a revised animation for 8 Oct and soon will make production runs, thanks to the assistance of a student at NWRA. several preliminary reports are also available to those who wish to take a peak. I have attached the animation for 8 Oct. If you cannot view it, you can download free VLC.
21 Oct
The wind direction for the three handars on the tower, on average, are about 5 degrees counterclockwise from the interpolated CSAT directions at the Handar levels. "Interpolated wind directions" are computed from interpolated U and V. Comparison of wind directions at the A stations are less systematic and are influenced by any physical height dependence between the 0.5 and 1.0 m levels. The profile of the wind direction based on averaged CSAT u and v show irregularities with height on the order of few degrees. It is not known if these differences are instrumental or physical. The most suspicious tendency is an enhanced value of the u-component for the 4 m CSAT of about 5 cm/s compared to the neighboring CSATs. While such differences should be recognized in analysis of the data, they are not a serious difficulty for the analysis. More investigation is need. In general, the data look very good.
17 Oct
I have attached a pdf of a preliminary case study for 7-8 Sept that I have been working on in the past week.. Both the figures and text will be improved but the current version provides an impression of some of the interesting interactions not previously examined in the literature.
17 Oct
I stopped posting the human transect results after the first few initial attempts. While they are useful for exploring different regions just outside the domain, the quantitative information along fixed transects is of limited use. There is too much transient variability and the pre-sunrise and post-sunset periods are too short for enough transects. I had forgotten that over flat ground, the dawn and twilight periods are shorter than in complex terrain where the sun goes behind the mountains early etc.
24 Sept
Ben Balsley will not be carrying out any Data Hawk flights during SCP. He learned that in fact he does need FAA approval which requires several months.
Danijel Belusic found out today that shipment of his nanobarometers have been delayed due to the large demand. This was a last minute long shot anyway.
Jielun Sun is attempting to create digitized elevation for the SCP site using the theodolite. This information will be eventually combined with the accurate experiment-averaged GPS elevation for each station. Next year, NEON intends to carry out lidar-measured elevation that includes the SCP site.
15 Sept
There have been some concerns about the success of the experiment if October and November are cloudier or windier than indicated by the existing data from the Pawnee Grasslands. Not to worry. Even on cloudy windy nights, the topography will modify the flow through partial sheltering. Although this is not the primary purpose of the proposed work, all nights will be of some interest. On clear windy nights, barring strong winds, some stratification will develop in the valley which will modify the flow even if drainage flows and a cold pool do not develop. Our primary interest is development of drainage flows that are only intermittent or distorted by the larger scale flow. These common cases have not been studied before. Of course very calm clear nights where drainage flows and the cold pool dominate will also be analyzed in detail. Basically, we are interested in whats out there rather than verification of text book thinking.
FIELD NOTES
These notes are partitioned as
1. General comments on the topography vs the topo maps
2. Two flagged observing transects for the human tram
3. Daily notes
GENERAL COMMENTS
For most of the network, the topographical map agrees with what one sees
at a given station, subject to the issue that the slope vector at a given
point depends on scale of estimation. And of course an observer is
rather objective as well. However, an observer also notes gentle topographical features that are not resolved by the topographical map that should substantially change the course of a trajectory at 1 m. Eventually (allegedly) NEON will fly laser altimetry over our area.
The biggest differences are in the western part of the network and west
and southwest of the network where the slopes are quite weak and not resolved by the topo maps. In particular, large relatively flat areas to the west and southwest of the domain (but still east of the highway) will drain into the gully occupied by A3 or drain into the main gully further east of A3, even east of A7. The air west of A1 will actually be diverted to the SE and feed into the A3 gully as well. The airshed for the A1-A2 gully is at LEAST an order of magnitude smaller than that for the A3 gully, while a large area to the SW also drains into the main gully from A7 eastward.
The gully defined by A1-A2-A5 probably does not contribute that significantly as a source region for the main gully but is of interest in its own right. Its airshed is well contained and relatively simple.
The slope at A14 is directed more westward than on perceives from the gully and thus would not reflect flow down the transect toward the gully. This feature is resolved by the topo maps
The slope north of A16 only partly drains toward the gully. A secondary gully diverts much of the air toward the east that merges near the junction of our gully and the north-south gully. This is missed by the topomaps and probably explained why A15 at its former position was not detecting side slope flow.
The confluence east of C tower needs more study
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
The local transects. approximate numbers are in meters. ** denotes flag
THE A1 NETWORK
**
70
*-- 120 --* - 70 - A1 --- 70 --- **
THE C TOWER EAST AND SOUTH
C tower 70 m ** 70 m * 70 m *
140 m
**
58 m
**
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2 Oct morning, mostly clear 20-30% alto cu, cirrus. this is prior to flagging of the C transect
MST 0700 0715 730
house 9.0 8.2
slope top 8.3 7.0
slope bot 6.0
station C 5.5 4.8 5.8
midway 4.9 5.0 5.2
fence 5.1 5.6 6.1
Evening of 2 Oct, substantial cooling, difference between the top and bottom of the gully about 2 C; winds decreasing but still substantial
3 Oct 630 morning some wind; roughly everywhere = 12 C
3 Oct evening; little variation
4 Oct morning: little variation
4 Oct, evening
evening clear and relatively calm but little spatial variation at dusk, even though significant stratification is observed on the tower. the air temperature is much cooler than the soil temperature.
5 Oct morning and evening. overcast, no sampling
6 Oct morning overcast no sampling