Geoscience Reference
In-Depth Information
Results presented below were derived from observations collected from Vaisala RS-80
sondes (from 41.38ºN, 2.12ºE and 98 m asl) which sampled every 10 s providing much
higher vertical resolution than the usual standard operational radiosounding observations.
This allowed better characterization of the air refractive index variability and the detection
of thinner super refractive layers that may not be detected by standard radiosounding
observations but may have significant effects in the propagation of the radar beam. Most
results presented in this and the next section, are based on data collected between 1997 and
2002, at 00 and 12 UTC in Barcelona (Bech et al., 1998, 2000, 2002). From the original 2485
radiosoundings available, 86% passed the quality control process (based both in data format
and content analysis, adapted from Météo-France, 1997).
3.1 Surface refractivity
Surface refractivity is an important factor in radiometeorology; it appears in the refractivity
exponential model and is one of the terms used in the standard computation of the VRG
(ITU, 2003). Table 2 shows Barcelona
N
s
statistics.
00Z
MONTH
Mean
St_dev
Min
P25
P50
P75
Max
J
315
8
291
310
315
320
335
F
317
10
293
309
318
325
334
M
316
10
296
310
319
323
334
A
320
10
292
314
322
329
335
M
329
13
294
319
332
339
351
J
341
13
297
334
343
350
366
J
347
15
302
336
351
357
372
A
354
15
303
346
355
364
382
S
344
13
309
338
345
354
371
O
336
14
305
326
335
347
367
N
316
13
286
309
314
321
367
D
313
11
284
305
312
318
339
Total 00Z
330
19
284
315
328
346
382
12Z
MONTH
Mean
St_dev
Min
P25
P50
P75
Max
J
312
10
286
305
311
317
340
F
309
11
284
302
310
317
331
M
316
12
292
306
316
324
342
A
313
13
268
306
315
324
336
M
326
13
300
316
328
336
352
J
335
13
285
326
338
344
367
J
341
16
265
332
341
352
388
A
344
16
298
331
345
356
369
S
337
17
300
322
340
350
368
O
328
15
299
316
327
340
359
N
312
12
283
305
311
319
348
D
311
11
278
303
310
318
338
Total 12Z
325
18
265
312
324
339
388
Total
00Z & 12Z
327
19
265
313
325
341
388
Table 2. N
s
statistics for Barcelona calculated from 00Z and 12Z data.
