Example 5. Nonauthoritative Dimension Descriptors (Ozonesondes)

This example is an extension of the previous example and is a more realistic specification of ozonesondes. This example looks at a very small set of data, but the data varies over all dimensions. Again, consider a data object consisting of balloon-borne observations of ozone concentrations at varying pressure levels, this time over a set of 4 stations (1001, 1002, 1003, 1004) on 3 days (21-23 August 1992). Our Level 0 dimension will consist of ozone concentration. The Level 1 dimension will be the pressure levels at each station where the observations are recorded. There will be one Level 2 dimension consisting of a generic index. The station identifiers and the date (specified as yymmdd, where yy = last two digits of year, mm = month number, and dd = day of month) will be additional descriptions for the Level 2 dimension. This is the general way to specify multiple varying Level 2 dimensions.

The observations are taken as follows: On 21 August 1992, station 1001 reported observations at 15 pressure levels, station 1002 at 19 pressure levels, station 1003 at 18 pressure levels, and station 1004 did not report. On 22 August 1992, station 1001 reported observations at 6 pressure levels, station 1002 at 11 pressure levels, station 1003 at 20 pressure levels, and station 1004 at 22 pressure levels. On 23 August 1992, station 1001 reported observations at 12 pressure levels, station 1002 at 17 pressure levels, station 1003 did not report, and station 1004 at 13 pressure levels. In this case, the data object dimensional record fields will be as follows (indices start at 0):

OBJDESC.

NDIM0 = 1

NDIM1 = 1

NDIM2 = 1

NDIM3 = 0

DIMSPEC0.

INDEX = -1

GPTNUM = 1

DIMSPEC1.

INDEX = 0

DESNUM = 10

DIMSPEC2.

INDEX = 1

GPTNUM = 10

DESCRIP0.

DATFMT = single precision floating-point

VARTYPE = ozone concentration

UNITS = ppmv

DESCRIP1.

DEXSORT = 0

NDEX = 0

RECSORT = 0

START = 0

END = 0

GPTNUM = 15

DUPNUM = 0

DESSUP = 0

DESFMT = single precision floating-point

DESTYPE = pressure

UNITS = mb

STORG = 0

DESCVAL.

DLEVEL = 1

LEVEL = 1

DINDEX = 0

DEXSORT = 0

NDEX = 0

RECSORT = 0

AVALS = (list of 15 pressure levels)

DESCRIP1.

DEXSORT = 65536

NDEX = 0

RECSORT = 1

START = 1

END = 1

GPTNUM = 19

DUPNUM = 0

DESSUP = 0

DESFMT = single precision floating-point

DESTYPE = pressure

UNITS = mb

STORG = 0

DESCVAL.

DLEVEL = 1

LEVEL = 1

DINDEX = 0

DEXSORT = 65536

NDEX = 0

RECSORT = 1

AVALS = (list of 19 pressure levels)

DESCRIP1.

DEXSORT = 131072

NDEX = 0

RECSORT = 2

START = 2

END = 2

GPTNUM = 18

DUPNUM = 0

DESSUP = 0

DESFMT = single precision floating-point

DESTYPE = pressure

UNITS = mb

STORG = 0

DESCVAL.

DLEVEL = 1

LEVEL = 1

DINDEX = 0

DEXSORT = 131072

NDEX = 0

RECSORT = 2

AVALS = (list of 18 pressure levels)

DESCRIP1.

DEXSORT = 196608

NDEX = 0

RECSORT = 3

START = 3

END = 3

GPTNUM = 6

DUPNUM = 0

DESSUP = 0

DESFMT = single precision floating-point

DESTYPE = pressure

UNITS = mb

STORG = 0

DESCVAL.

DLEVEL = 1

LEVEL = 1

DINDEX = 0

DEXSORT = 196608

NDEX = 0

RECSORT = 3

AVALS = (list of 6 pressure levels)

DESCRIP1.

DEXSORT = 262144

NDEX = 0

RECSORT = 4

START = 4

END = 4

GPTNUM = 11

DUPNUM = 0

DESSUP = 0

DESFMT = single precision floating-point

DESTYPE = pressure

UNITS = mb

STORG = 0

DESCVAL.

DLEVEL = 1

LEVEL = 1

DINDEX = 0

DEXSORT = 262144

NDEX = 0

RECSORT = 4

AVALS = (list of 11 pressure levels)

DESCRIP1.

DEXSORT = 327680

NDEX = 0

RECSORT = 5

START = 5

END = 5

GPTNUM = 20

DUPNUM = 0

DESSUP = 0

DESFMT = single precision floating-point

DESTYPE = pressure

UNITS = mb

STORG = 0

DESCVAL.

DLEVEL = 1

LEVEL = 1

DINDEX = 0

DEXSORT = 327680

NDEX = 0

RECSORT = 5

AVALS = (list of 20 pressure levels)

DESCRIP1.

DEXSORT = 393216

NDEX = 0

RECSORT = 6

START = 6

END = 6

GPTNUM = 22

DUPNUM = 0

DESSUP = 0

DESFMT = single precision floating-point

DESTYPE = pressure

UNITS = mb

STORG = 0

DESCVAL.

DLEVEL = 1

LEVEL = 1

DINDEX = 0

DEXSORT = 393216

NDEX = 0

RECSORT = 6

AVALS = (list of 22 pressure levels)

DESCRIP1.

DEXSORT = 458752

NDEX = 0

RECSORT = 7

START = 7

END = 7

GPTNUM = 12

DUPNUM = 0

DESSUP = 0

DESFMT = single precision floating-point

DESTYPE = pressure

UNITS = mb

STORG = 0

DESCVAL.

DLEVEL = 1

LEVEL = 1

DINDEX = 0

DEXSORT = 458752

NDEX = 0

RECSORT = 7

AVALS = (list of 12 pressure levels)

DESCRIP1.

DEXSORT = 524288

NDEX = 0

RECSORT = 8

START = 8

END = 8

GPTNUM = 17

DUPNUM = 0

DESSUP = 0

DESFMT = single precision floating-point

DESTYPE = pressure

UNITS = mb

STORG = 0

DESCVAL.

DLEVEL = 1

LEVEL = 1

DINDEX = 0

DEXSORT = 524288

NDEX = 0

RECSORT = 8

AVALS = (list of 17 pressure levels)

DESCRIP1.

DEXSORT = 589824

NDEX = 0

RECSORT = 9

START = 9

END = 9

GPTNUM = 13

DUPNUM = 0

DESSUP = 0

DESFMT = single precision floating-point

DESTYPE = pressure

UNITS = mb

STORG = 0

DESCVAL.

DLEVEL = 1

LEVEL = 1

DINDEX = 0

DEXSORT = 589824

NDEX = 0

RECSORT = 9

AVALS = (list of 13 pressure levels)

DESCRIP2.

NDEX = 0

DUPNUM = 2

DESSUP = 0

DESFMT = long integer

DESTYPE = generic index

UNITS = no units

STORG = 1

DESCVAL.

DLEVEL = 2

LEVEL = 2

DINDEX = 0

DEXSORT = 0

NDEX = 0

RECSORT = 0

AVALS = (0, 1)

DESCRIP.

LEVEL = 2

DEXSORT = 0

NDEX = 0

RECSORT = 0

DESSUP = 0

DESFMT = long integer

DESTYPE = station identifier

UNITS = no units

STORG = 0

DINDEX = 1

DESCVAL.

DLEVEL = 6

LEVEL = 2

DINDEX = 1

DEXSORT = 0

NDEX = 0

RECSORT = 0

AVALS = (1001, 1002, 1003, 1001, 1002, 1003, 1004, 1001, 1002, 1004)

DESCRIP.

LEVEL = 2

DEXSORT = 0

NDEX = 0

RECSORT = 0

DESSUP = 0

DESFMT = long integer

DESTYPE = time

UNITS = YYMMDD

STORG = 0

DINDEX = 2

DESCVAL.

DLEVEL = 10

LEVEL = 2

DINDEX = 2

DEXSORT = 0

NDEX = 0

RECSORT = 0

AVALS = (920821, 920821, 920821, 920822, 920822, 920822, 920822, 920823, 920823, 920823)

Note that the START and END fields of DESCRIP1 contain the indices for the days and stations over which the different pressure level definitions apply. This is explained further in Section 2.3.2. The DESCVAL record associated with each DESCRIP1 record contains the appropriate values of pressure.

These START and END fields lead us into the next set of examples.