NMQ Verification System (QVS) Tutorial

Figure 30. The NMQ 3-D Mosaic domain and computational tiles.

Appendix B: 3D Mosaic

The National 3D Mosaic is a major component of the NSSL's National Mosaic and QPE (NMQ) system. The NMQ domain and the radar locations are shown in Figure 30, at right.

The domain parameters are shown in Table 1, below. The grid resolution in the west-east direction is dx (lon) = 0.01° . This is approximately 1.045km at the southern bound of the domain and about 0.638km at the northern bound of the domain. The grid resolution in north-south direction is dy (lat) = 0.01° which is 1.112km everywhere.

There are 31 vertical levels in the 3D Mosaic grid. The height of each level is listed in Table 2.

**Table 1.** Domain parameters for the national 3D reflectivity mosaic system
Tile ID	ctrlat (°N)	ctrlon (°W)	nx	ny	nz	SW corner	NE corner
1	47.5	120	2001	1501	31	40, -130	55, -110
2	47.5	100	2001	1501	31	40, -110	55, -90
3	47.5	85	1001	1501	31	40, -90	55, -80
4	47.5	70	2001	1501	31	40, -80	55, -60
5	30	120	2001	2001	31	20, -130	40, -110
6	30	100	2001	2001	31	20, -110	40, -90
7	30	85	1001	2001	31	20, -90	40, -80
8	30	70	2001	2001	31	20, -80	40, -60

**Table 2.** Height of each level in the NSSL CONUS reflectivity mosaic grid
Level #	Height (km above MSL)
1	0.5
2	0.75
3	1
4	1.25
5	1.5
6	1.75
7	2
8	2.25
9	2.5
10	2.75
11	3
12	3.5
13	4
14	4.5
15	5
16	5.5
17	6
18	6.5
19	7
20	7.5
21	8
22	8.5
23	9
24	10
25	11
26	12
27	13
28	14
29	15
30	16
31	18

The 3-D reflectivity mosaic product is obtained via two steps: 1) objectively analyzing volume scan base reflectivity data (quality controlled) from their native coordinates (spherical) onto a 3-D regular Cartesian grid (so called "single radar Cartesian" grid, or cubes). Each cube is centered at the radar site and encompasses either 460km radar umbrella (for coastal radars and radars located along the US-Canada and US-Mexico boundaries, Zhang et al. 2006) or 300km radar umbrella (for inland radars). The single radar cubes are then merged to produce the CONUS 3-D mosaic via a distance weighted mean scheme. Detailed information about the single radar Cartesian grid and mosaic can be found in the following references:

Zhang, J., K. Howard, and S. Wang, 2006: Single radar Cartesian grid and adaptive radar mosaic system. Preprints, The 12th Conference on Aviation, Range, and Aerospace Meteorology, Atlanta, GA, USA, Amer. Meteor. Soc., CD-ROM, 1.8.

Zhang, J., K. Howard, and J.J. Gourley, 2005: Constructing three-dimensional multiple radar reflectivity mosaics: examples of convective storms and stratiform rain echoes. J. Atmos. Ocean. Tech., 22, 30-42.