Figure 1. View of the Radar Wind Profiler from the
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<> <>Figure 2. Radar Wind Profiler Sample Case Study
<>Here, the arrows indicate horizontal, two-dimensional winds (vector pointing upward indicates a southerly wind). The exhibited behavior is consistent with approaching warm front as observed based on MODIS satellite imagery observing a cloud line. (vertical line indicates time of the plots [0700 EST]). Low-altitude winds measured are northeasterly, while the winds aloft between 1.5 and 2.0 km above ground are southerly. <>Besides using the wind profiles for dispersion for hazard management purposes, a variety of meteorological applications can benefit from a combination of radar profilers and lidar-aerosol wind profilers. Perhaps most important, convective mixing height has been a relevant parameter for climate studies, urban heat island as well as conventional dispersion models, and becomes even more important in advanced models where the intensity of turbulence under convective conditions is assumed to be strongly related to CBL height. For example, SODAR profiles can be very useful for obtaining SODAR Boundary Layers (SBL). However, the SBL mixing height determination is plagued by different problems. On one hand, turbulence in the outer SBL often is intermittent and patchy, so that it is very difficult to measure the height up to which turbulence extends. The other problem is that the backscatter intensity, on which mixing height estimation from sodar data in the SBL usually relies, depends not only on turbulent fluctuations of the refractive index but also on its mean gradient. In this case, the mixing height determined from the sodar output maybe the top of the stable layer which has developed due to radiative cooling rather than the top of the mixing layer.
On the other hand, aerosol lidars whose backscatter profiles indicate the aerosol concentration profiles, have also been used in the determination of mixing height. This correspondence is usually very good during daytime where convective heating is dominant. However, the problem with this approach is that the height where a significant decrease of the aerosol concentration is observed does not need to coincide with the current mixing height. Instead, it may often represent the top of a reservoir layer, built up on a previous day. An example of this phenomenon is exhibited in figure 3.
Figure 3. a) Aerosol Lidar Observations b) CBL Height from CMAQ model compared to both growing and residual layer. In particular, we note that the convective boundary layer height follows the growth mode of the aerosol layer fairy well but a significant residual layer is present. Care must be made to isolate these multiple layers. The purpose of this presentation is to provide an update on installation upgrades and operations of the New York City Meteorological Network (NYC MetNet). Beside providing an important service to the New York City Metropolitan Area by supplying useful and timely air transport information, the network may act as a test bed for advanced studies of the dispersion of air particles under complex conditions with applications ranging from social concerns to military operations and government planning. To enhance the networks reach and performance, we have made a number of upgrades and preliminary tests for new installations. A description of the network will be given which includes operations, upgrades and the dissemination of quality assured data. Acknowledgement This work was partially supported by the NOAA Interdisciplinary Scientific Environmental Technology (ISET)
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