| PEAC Home | Background | What's New? | ENSO and Climate | Tropical Storms |
| Seasonal Outlooks | Pacific Enso Update | Island Info & Maps | In the News | Useful Links |
July - August - September (JAS) 2008
The following sections describe: (i) the Canonical Correlation Analysis (CCA)-based forecasts for the monthly MEAN and MAXIMUM sea level deviations in the July - August - September (JAS) 2008 season, and (ii) the monthly sea level deviations observed in the previous season (May - June - July 2008). See Figure 2 at right for location of USAPI tide guage stations.
All units are in inches. 'Deviation’ is defined here as 'the observed or forecast difference between the monthly mean [or maximum] and the climatological monthly mean values (from the period 1975- 1995) computed at each station’. Also, note that the forecasting technique adapted here does not account for sea level deviations created by other atmospheric or geological conditions such as tropical cyclones, storm surges or tsunamis.
(i) Seasonal Sea Level Outlook for July - August - September (JAS) 2008
Based on the independent SST values observed in the April-May-June 2008 season, the resulting CCA model has been used to forecast the sea-level for the JAS 2008 season (see Table 1).
Table 1 : Forecasts of MEAN and MAX sea level deviation in inches for JAS 2008
Tide Gauge Station Honolulu, Hawaii Hilo, Hawaii (*) Data Unavailable.
Values for Chuuk (**) are guesstimated based on estimates from neighboring tide stations and observations from WSO Chuuk.
Deviations between 0~±1 inch are considered to be negligible and are denoted by ***.
Deviations withing the range of (+/-) 2 inches are unlikely to cause any advers climatic impact. Remarks: The positive sea-level deviations forecast for the JJA season (above) indicate that sea levels will remain slightly elevated at all USAPI stations for another 1 to 3 months. Although the ocean has returned to an ENSO neutral state, conditions across much of the Pacific still reflect La Niña. The sea level in the Pacific Islands is sensitive to the ENSO cycle, with falling sea level observed during El Niño years and rising sea level during La Niña years. Mean sea levels are expected to remain 0 to 6 inches above average during the JAS season. As compared to median values (presented in parenthesis in the right column), the MAXIMUM sea level may reach 2 to 4 inches higher than the median value.
(ii) Observed Monthly Sea Level Deviation in May-June-July (MJJ) 2008
The monthly time series (May-July 2008) for sea level deviations have been taken from the UH Sea Level Center. Consistent with the recent transition from La Niña to ENSO neutral conditions, positive deviations have been observed in most stations since January 2007. The observed values of seasonal mean/max sea level deviations was positive at all stations in July. As compared to June, some stations recorded slight rise (Malakal, Honolulu, Hilo) while others recorded a slight fall (Yap, Kwajalein, Pago Pago). Sea-levels at all stations are expected to begin falling toward normal levels in the next several months, as the residual effects of the La Niña disappear.
Table 2 : Observed MEAN and MAX sea level deviation in inches for MJJ 2008
Honolulu, Hawaii Hilo, Hawaii * Denotes where data is unavailable. ** Sea level data for Chuuk is based on estimates from neighboring tide stations (Yap and Pohnpei) and observations from WSO Chuuk.
Click here for more sea level information and products.
|
Pacific ENSO Applications Climate Center