Indice NAO. Pronóstico o consecuencia?

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Indice NAO. Pronóstico o consecuencia?
« en: Domingo 14 Febrero 2010 04:57:56 am »
Hoy estoy preguntón.

No se si ya se ha hablado de ésto pero no lo encuentro con el buscador.

Las estimaciones futuras del índice ya las podemos ver. La duda que tengo es:

Va antes el huevo o la gallina?, quiero decir, la previsión del índice siempre tiene reflejo en el futuro con lo que puede pasar?.. o se calcula según lo que ha pasado?

Quiero decir... se calcula según lo que va pasando o realmente indica lo que puede pasar y luego se modifica?, es un índice que muestra lo que va pasando?..


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Re: Indice NAO. Pronóstico o consecuencia?
« Respuesta #1 en: Domingo 14 Febrero 2010 09:53:38 am »
para las estimaciones se usan varios factores,

principalmente la recurrencia espacio-temporal, así como la "conexión" con otros índices  indicativos,
otros factores que se pueden evalúar son los biológicos (SOME REMARKS ON THE N.A.O. INDEX, RELATED OCEANOGRAPHIC FACTORS, AND ITS POSSIBLE FIT TO THE RECRUITMENT INDEX OF THE NORTH ATLANTIC SWORDFISH (Xiphias gladius), ICCAT WORKSHOP ON ENVIRONMENT AND TUNA ECRUITMENT, ambos de Jaime Mejuto, pero que no  encuentro en castellano)

este esd el método de la NOAA
Citar
2. North Atlantic Oscillation / Pacific - North American pattern (NAO/PNA)

Calculating the Daily PNA and NAO teleconnection indices

The calculation procedure and base period have changed for calculating the daily NAO and PNA teleconnection indices. These changes have been made to eliminate inconsistencies in the way that the monthly and daily indices are calculated.

The procedure used to calculate the daily PNA and NAO teleconnection indices is based on the Rotated Principal Component Analysis (RPCA) used by Barnston and Livezey (1987, Mon. Wea. Rev., 115, 1083-1126). This procedure isolates the primary teleconnection patterns for all months and allows time series of the patterns to be constructed. To obtain the teleconnection patterns, the RPCA technique is applied to monthly standardized 500-mb height anomalies obtained from the CDAS in the analysis region 20°N-90°N between January 1950 and December 2000. Click here for more information on the teleconnection pattern calculation procedures.

The monthly teleconnection patterns are now linearly interpolated to the day in question, and therefore account for the seasonality inherent in the NAO and PNA patterns. Previously, the annual mean PNA and NAO patterns were used, which were based on monthly non-standardized anomalies. The standardized anomalies are now calculated based on the 1950-2000 climatological daily mean and standard deviation, whereas the anomalies were previously calculated from the 1971-2000 base period daily means.

The daily teleconnection indices are now calculated using the Least Squares regression approach identical to that used for the monthly indices. Therefore, all of the teleconnection patterns valid for the day in question are now recognized when calculating the PNA and NAO indices. The daily indices now represent the combination of teleconnection patterns that accounts for the most spatial variance of the observed anomaly map on any given day. Previously, the indices represented the spatial correlation between the annual mean loading pattern of the NAO or PNA and the daily height anomalies, and did not account for the spatial overlap that exists amongst the various teleconnection patterns.2. North Atlantic Oscillation / Pacific - North American pattern (NAO/PNA)

Calculating the Daily PNA and NAO teleconnection indices

The calculation procedure and base period have changed for calculating the daily NAO and PNA teleconnection indices. These changes have been made to eliminate inconsistencies in the way that the monthly and daily indices are calculated.

The procedure used to calculate the daily PNA and NAO teleconnection indices is based on the Rotated Principal Component Analysis (RPCA) used by Barnston and Livezey (1987, Mon. Wea. Rev., 115, 1083-1126). This procedure isolates the primary teleconnection patterns for all months and allows time series of the patterns to be constructed. To obtain the teleconnection patterns, the RPCA technique is applied to monthly standardized 500-mb height anomalies obtained from the CDAS in the analysis region 20°N-90°N between January 1950 and December 2000. Click here for more information on the teleconnection pattern calculation procedures.

The monthly teleconnection patterns are now linearly interpolated to the day in question, and therefore account for the seasonality inherent in the NAO and PNA patterns. Previously, the annual mean PNA and NAO patterns were used, which were based on monthly non-standardized anomalies. The standardized anomalies are now calculated based on the 1950-2000 climatological daily mean and standard deviation, whereas the anomalies were previously calculated from the 1971-2000 base period daily means.

The daily teleconnection indices are now calculated using the Least Squares regression approach identical to that used for the monthly indices. Therefore, all of the teleconnection patterns valid for the day in question are now recognized when calculating the PNA and NAO indices. The daily indices now represent the combination of teleconnection patterns that accounts for the most spatial variance of the observed anomaly map on any given day. Previously, the indices represented the spatial correlation between the annual mean loading pattern of the NAO or PNA and the daily height anomalies, and did not account for the spatial overlap that exists amongst the various teleconnection patterns.
...
http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/history/method.shtml

o sea, que la predicción va antes, y se va modificando a medida que se adquieren datos, manteniendo el horizonte de predicción.



 
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