Wolfram Data Repository
Immediate Computable Access to Curated Contributed Data
Clear Air Radar Reflections in the CBL
Atmospheric Convective Boundary Layer reflectivity in dBZ units measured with a near-vertical profiling 33.4 GHz radar
Details
The data shown here were recorded on 17-20 February 2015 at Lawrence Livermore National Labs by the WiPPR radar system. The system was operating at an angle of 10 deg from the vertical. Each image spans approximately 1500 meters vertically and 24 hours horizontally. During the four day measurement period skies were clear. Radar echoes have been converted to the dBZ scale used in weather radar applications.
The convective boundary layer (CBL) is a turbulent region within about the first mile of the earth's surface. Turbulence is generated by the heat from the sun and airflow across the earth's surface. The maximum altitude of the CBL varies with time of day with maximum altitude occuring approximately at local solar noon and minimum altitude at night. The reulting turbulence modulates the velocity at which microwaves are propagated as a function of altitude of horizontal position. These modulations can be tracked in time and altitude by a sensitive radar even in clear sky conditions. This phenomena is referred to as clear air scatter.
The radar reflectivity data shown here is meaured on a dBZ scale. This is a frequency independent, logarithmic scale used in weather radar applications. The radar has 512 range gates with each gate spanning approximately 3.125 m in slant range. Additional data presented here include the following:
| ContactRate | radar range gates with contacts with greater than 2 dB SNR |
| TimeOfSolarNoon | time of solar noon (UST) |
| Day1To365 | day of recording |
| SolarRadiation | time history of clear day solar radiation in W/m2 |
| DBZMinMax | range of dBZ values in each image |
(4 elements)
Examples
Basic Examples (3)
Retrieve the data:
| In[1]:= | ![ResourceData[\!\(\*
TagBox["\"\<Clear Air Radar Reflections in the CBL\>\"",
#& ,
BoxID -> "ResourceTag-Clear Air Radar Reflections in the CBL-Input",
AutoDelete->True]\)]](https://www.wolframcloud.com/obj/resourcesystem/images/6d8/6d8b787c-57ba-4bf4-938d-b48f35ef780f/4c4a30931b547837.png){kind=small} |
| Out[1]= |  |
Get contact rates on the third day:
| In[2]:= | ![nday = 3;
images = ResourceData[\!\(\*
TagBox["\"\<Clear Air Radar Reflections in the CBL\>\"",
#& ,
BoxID -> "ResourceTag-Clear Air Radar Reflections in the CBL-Input",
AutoDelete->True]\)][[nday]]](https://www.wolframcloud.com/obj/resourcesystem/images/6d8/6d8b787c-57ba-4bf4-938d-b48f35ef780f/23e9a892f216281e.png){kind=small} |
| Out[3]= |  |
View the number of radar range gates with contacts as a function of universal standard time on day 3:
| In[4]:= | ![nday = 3;
contactRates = ResourceData[\!\(\*
TagBox["\"\<Clear Air Radar Reflections in the CBL\>\"",
#& ,
BoxID -> "ResourceTag-Clear Air Radar Reflections in the CBL-Input",
AutoDelete->True]\), "ContactRate"];
ListPlot[contactRates[[nday]], Sequence[
Axes -> False, Frame -> True, FrameLabel -> {"Universal Standard Time (hours)", "Range Gates with Contacts"}, AspectRatio -> 1, BaseStyle -> {FontSize -> 14}]]](https://www.wolframcloud.com/obj/resourcesystem/images/6d8/6d8b787c-57ba-4bf4-938d-b48f35ef780f/2ebd22dcd8c7f235.png) |
| Out[6]= |  |
Scope & Additional Elements (1)
Compare the observed contact rates to solar radiation as a function of time. Solar radiation (smooth blue curve) has been estimated with a standard model and scaled for comparison purposes:
| In[7]:= | ![contactRates = ResourceData[\!\(\*
TagBox["\"\<Clear Air Radar Reflections in the CBL\>\"",
#& ,
BoxID -> "ResourceTag-Clear Air Radar Reflections in the CBL-Input",
AutoDelete->True]\), "ContactRate"];
sr = ResourceData[\!\(\*
TagBox["\"\<Clear Air Radar Reflections in the CBL\>\"",
#& ,
BoxID -> "ResourceTag-Clear Air Radar Reflections in the CBL-Input",
AutoDelete->True]\), "SolarRadiation"];
ListPlot[Join[contactRates, {0.5 sr}], Sequence[
PlotRange -> {{0, 24}, {-10, 550}}, Axes -> False, Frame -> True, FrameLabel -> {"Universal Standard Time (hours)", "Range Gates with Contacts"}, AspectRatio -> 1, ImageSize -> 500, BaseStyle -> {FontSize -> 14}, PlotLegends -> {"17 Feb", "18 Feb", "19 Feb", "20 Feb"}, Epilog -> {{
Dashing[0.01],
Line[{{17, 300}, {24, 300}}]},
Style[
Text["\!\(\*600 W/m^2\)", {15, 310}], FontSize -> 14]}]]](https://www.wolframcloud.com/obj/resourcesystem/images/6d8/6d8b787c-57ba-4bf4-938d-b48f35ef780f/715515ec7fd426f7.png) |
| Out[9]= |  |
Visualizations (1)
Convert an image to a dBZ scale and display. The color black corresponds to no reflectivity. The horizontal lines are radar signal processing artifacts:
| In[10]:= | ![nday = 3;
images = ResourceData[\!\(\*
TagBox["\"\<Clear Air Radar Reflections in the CBL\>\"",
#& ,
BoxID -> "ResourceTag-Clear Air Radar Reflections in the CBL-Input",
AutoDelete->True]\)];
{a, b} = ResourceData[\!\(\*
TagBox["\"\<Clear Air Radar Reflections in the CBL\>\"",
#& ,
BoxID -> "ResourceTag-Clear Air Radar Reflections in the CBL-Input",
AutoDelete->True]\), "DBZMinMax"][[nday]];
dbz = ImageData@ImageReflect[ImageApply[# (b - a) + a &, images[[nday]]]];
ReliefPlot[dbz, Sequence[
PlotRange -> {b - 50, b - 10}, FrameTicks -> True, DataRange -> {{0, 24}, (Sin[80 Degree] 3.125) {0, 512}}, AspectRatio -> 0.4, ImageSize -> 800, FrameLabel -> {"Universal Standard Time (hours)", "Altitude (m)"}, BaseStyle -> {FontSize -> 14}, PlotLegends -> BarLegend[Automatic, LegendLabel -> "dBZ"], ClippingStyle -> {Black, Yellow}]]](https://www.wolframcloud.com/obj/resourcesystem/images/6d8/6d8b787c-57ba-4bf4-938d-b48f35ef780f/2dee1710c12b8019.png) |
| Out[14]= |  |
Bibliographic Citation
Marshall Bradley, "Clear Air Radar Reflections in the CBL" from the Wolfram Data Repository (2026)