## 3 Results
### Composites  
Composites were utilized to further explore the dynamics associated with high sea levels off the south coast of Jamaica during summer. The detrended Jamaica sea level anomaly data were averaged for June to September, and the resulting timeseries was divided into quartiles. Six high summer sea level years (75 th quartile) and six low summer sea level years (25 th quartile) are shown in Table 5. They were also classified according to whether they fell in years during which the Pacific experienced El Nino or La Nina conditions. Four out of six high summer sea level years associated with warm equatorial Pacific conditions during the summer months (classified as El Nino), while three of six low summer years coincided with cool Pacific conditions (La Nina). The EOF analysis had previously indicated significant correlations with equatorial Pacific SST anomalies. Composites of summer SST and wind strength anomalies over the Atlantic and eastern Pacific were created for the high years, low years, as well as for the difference between high and low years (Figure 6). Statistically significant differences were hatched on the difference maps. \begin{table}
\begin{tabular}{c c c} \hline  & **Low Sea Level Years** & **High Sea Level Years** \\ \hline El Niño & & 1994, 2015, 2018, 2019, \\ \hline La Nina & 1999, 2007, 2011 & 2008 \\ \hline Neutral & 2005, 2006, 2013 & 2003 \\ \hline \end{tabular}
\end{table} 
Table 5: High and low summer sea level anomaly years for Jamaica classified according to ENSO modes of variability. High (low) sea level years correspond to the 75 th (25 th) quartile. ENSO mode determined using the Oceanic Niño Index (ONI), accessed from [[https://origin.cpc.nceep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php](https://origin.cpc.nceep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php)]([https://origin.cpc.nceep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php](https://origin.cpc.nceep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php)) (accessed on 1 November 2022). High sea level years are characterised by an SST gradient between the tropical Atlantic and equatorial Pacific. Warm SST anomalies occur across the parts of the equatorial, north, and eastern tropical Pacific captured in the domain. There is evidence of a warm tongue across the equator, characteristic of an El Nino event, as well as SST maxima at 20\({}^{\circ}\) N and northward of 40\({}^{\circ}\) N off the west coast of America. Temperatures are up to 0.5 \({}^{\circ}\)C greater than average for the summer season. In contrast, cool anomalies dominate the Caribbean basin and north tropical Atlantic up to 20\({}^{\circ}\) N. Warm anomalies exist in the far north Atlantic. The low sea level composite shows a reversal in the pattern, with, notably, a cool equatorial Pacific and warm north tropical Atlantic pattern being present. The difference map highlights that the changes seen in the Caribbean basin and north Atlantic, as well as the equatorial and north tropical Pacific, are statistically significant. The corresponding composite wind maps show that, for high summer sea level years, wind strength across the entire Caribbean basin is higher, with a maximum in the southwestern basin in the vicinity of the CLIJ. Stronger winds stretch across the Central American isthmus with a narrow tongue stretching westward into the Pacific (to 120\({}^{\circ}\) W) from the west coast of Costa Rica. Weaker winds just north of the equator stretch westward from Panama and parallel the strong winds noted previously. The composite for low sea level years shows a reversal of the above pattern with weaker winds in the Caribbean basin and  
Figure 6: Composite of sea surface temperatures (**left panels**) and ERA5 Reanalysis resultant wind (**right panels**) for (**a**) high summer sea level years, (**b**) low summer sea level years, (**c**) difference between high and low years. Hatching in (**c**) indicates regions with statistically significant difference. a minimum in the vicinity of the CLLJ.