Lobos de Afuera (Peru) Site History
History Summary
| Station Name | Lobos de Afuera |
|---|---|
| Country | Peru |
| Latitude | 06° 56.0' S |
| Longitude | 080° 43.0' W |
| GLOSS No. | None |
| Time Reference | GMT (hours 00-23) |
| Contributor | Direccion Hidrografia y Navegacion de la Marina
and Atlantic Oceanographic and Meteor. Lab. (AOML) |
| Instrument Type | Standard mechanical tide gauge (1982-present)
Leupold Stevens analog-to-digital recorder (ADR)(5/1985-present) (backup) Handar Encoder (ENC) model 436A (12/1985-present)(backup) |
| Site of Gauge | No data |
| Observational Period | 1982 - 1994 |
Reference Level
The data which were given to the AOML by the originator contained many reference level shifts. The tide staff comparison readings explained only a few of the shifts. The following shifts were adjusted by the AOML using the comparative readings, comparisons with the ADR data, and estimations based on the daily values and hourly residuals (observed data minus predicted tides):
| Period
(day/month/year) |
Value added
to Original(mm) |
|---|---|
| 14/11/82 - 15/11/82 | -150 |
| 15/11/82 - 17/11/82 | -300 |
| 01/06/83 - 10/09/83 | -250 |
| 11/09/83 - 22/10/83 | -130 |
| 23/10/83 - 31/12/83 | +120 |
| 01/01/84 - 31/12/84 | +120 |
| 18/03/84 - 31/05/84 | - 50 |
| 12/07/84 - 24/08/84 | + 50 |
| 01/09/84 - 15/09/84 | -300 |
| 16/09/84 - 22/09/84 | +350 |
| 23/09/84 - 30/09/84 | -250 |
| 20/10/84 - 23/10/84 | - 50 |
| 01/11/84 - 05/11/84 | -200 |
| 06/11/84 - 19/11/84 | -350 |
| 20/11/84 - 30/11/84 | -450 |
| 01/12/84 - 31/12/84 | -300 |
| 01/02/85 - 28/02/85 | +230 |
| 01/05/85 - 28/05/85 | +328 |
| 01/08/85 - 31/08/85 | +328 |
| 01/09/85 - 31/09/85 | +533 |
| 01/10/85 - 31/10/85 | +472 |
| 01/11/85 - 31/12/85 | +625 |
| 01/01/86 - 20/01/86 | +580 |
| 21/01/86 - 31/01/86 | +275 |
| 01/06/86 - 13/06/86 | +350 |
| 13/06/86 - 28/06/86 | + 40 |
| 29/06/86 - 21/07/86 | - 60 |
| 22/07/86 - 30/09/86 | + 40 |
| 01/12/86 - 31/12/86 | + 60 |
| 01/01/87 - 14/06/87 | + 55 |
| 01/08/87 - 31/08/87 | -183 |
The following level shifts in the analog data were adjusted by JASL based on analysis of the hourly residuals and comparisons with daily data from adjacent stations: Callao, Peru and La Libertad, Ecuador, and with daily data from the ADR and ENC sensors.
| Period
((hour)day/month/year) |
Value added
to Original (mm) |
|---|---|
| (00)01/07/82 - (05)26/03/83 | -110 |
| (06)01/11/83 - (13)21/11/83 | - 75 |
| (02)01/12/83 - (18)12/08/84 | + 75 |
| (04)01/09/84 - (13)20/11/84 | - 70 |
| (05)01/10/87 - (15)16/10/87 | -150 |
| (13)11/11/87 - (05)01/12/87 | + 60 |
| (06)01/12/87 - (03)16/04/88 | - 60 |
| (04)16/04/88 - (16)10/06/88 | -100 |
| (17)10/06/88 - (23)11/06/88 | -240 |
| (00)12/06/88 - (23)30/09/88 | -160 |
| (20)19/02/89 - (18)01/03/89 | +75 |
| (12)20/07/89 - (12)19/08/89 | +75 |
| (00)02/02/92 - (12)16/02/92 | +75 |
| (13)16/02/92 - (08)01/03/92 | -120 |
| (00)11/10/93 - (16)01/12/93 | 80 |
The above adjustments are uncertain to a few cm. In addition to the above adjustments, the original data from 10/1988 - 05/1994 were adjusted by -160 cm based on the overlap of August-Sept/1988 with the existing time series in the TOGA archive.
Quality Assessment by the UH Sea Level Center
The following gaps were replaced with data from the redundant sensors, primarily the ENC, which were received via satellite and quality-controlled at the UH Sea Level Center:
| Period
((hour)day/month/year) |
|---|
| (05)01/03/86 - (10)02/04/86 |
| (00)26/04/86 - (23)31/05/86 |
| (00)26/06/86 - (09)01/07/86 |
| (08)29/10/86 - (09)13/11/86 |
| (00)29/06/87 - (20)01/08/87 |
| (01)01/09/87 - (23)30/09/87 |
| (05)04/10/87 - (11)05/10/87 |
| (00)17/10/87 - (10)19/10/87 |
| (06)10/11/87 - (11)11/11/87 |
| (02)27/02/88 - (21)29/02/88 |
| (00)01/06/88 - (09)02/06/88 |
| (05)01/10/89 - (04)01/11/89 |
| (12)05/04/90 - (04)13/04/90 |
| (00)27/07/91 - (19)14/08/91 |
| (13)26/12/91 - (04)01/02/92 |
| (00)11/11/93 - (23)17/11/93 |
Based on differences of the data with redundant data received at the UH Sea Level Center via satellite, the accuracy of the daily values appears to be no better than ±5 cm.
| Year | CI (%) | Missing Data | Replaced Gaps or Bad Data | Questionable Fluctuations | |
|---|---|---|---|---|---|
| 1982 | 46 | 226-229,274-280, 324-326,335-341 | (17)321-(11)322 | 217,266 | |
| 1983 | 86 | 85-134,243-244 | none | 239-241,251-252,256-257,260-261,264,294-296,361-362 | |
| 1984 | 89 | 72-78,153-154,166-169,173-174,175-194,275-287 | (23)174-(15)175
(02)230-(15)230 (01)274-(13)274 |
4-9,22-24,39-40,67-70,78-81,93-98,136, 139,152,160-161,164,169,238-239,251,327-332,343-344,350,355-356 | |
| 1985 | 74 | 1-32,43-44,60-121 | none | 37,40-43,49-50,52- 53,123-125,131,155 | |
| 1986 | 100 | none | none | 4-6,9-10,12-13,16,29-30,96-97,258-259 | |
| 1987 | 99 | 269-271 | (02)137-(08)137
(10)208-(16)208 (05)305-(12)305 (13)321-(22)321 (02)322-(21)322 (10)340-(04)341 (11)351-(19)351 |
88,122,138-139,141, 149,151,166-167 | |
| 1988 | 100 | none | (05)010-(04)011
(17)051-(01)052 (17)065-(04)066 (18)117-(00)118 (20)215-(19)216 (03)229-(12)229 (06)237-(23)237 |
none | |
| 1989 | 100 | none | (09)027-(18)027
(09)050-(19)050 (03)273-(10)273 |
63-65,160-161 | |
| 1990 | 100 | none | (05)168-(04)169
(20)229-(13)230 (05)276-(14)276 (02)332-(11)332 (13)335-(01)336 (00)345-(11)345 |
118-119,121-125,130 | |
| 1991 | 100 | none | (18)077-(04)078
(04)182-(11)182 (05)213-(13)213 (20)284-(14)285 (01)305-(12)305 (05)359-(00)360 |
92-119 | |
| 1992 | 100 | none | (13)039-(23)039
(21)107-(04)108 (17)199-(08)200 (22)213-(23)213 (01)214-(08)214 (07)229-(17)229 (05)336-(12)336 |
81-82,153-182,212-213 | |
| 1993 | 100 | none | none | none | |
| 1994 | 33 | none | none | none |
