Fig. 1

The distribution of average ocean heat content anomaly within the depth range of 0 to 2000 m in the Northwest Pacific from 2004 to 2023, corresponding to typhoon tracks (solid gray lines), typhoon generation locations (blue triangles), typhoon maximum wind speed locations (green triangles), and typhoon dissipation locations (red triangles)"

Fig. 2

The frequency of typhoons in the Northwest Pacific from 2004 to 2023 (a) and the time series of ocean heat content anomaly in the middle and upper layers (b). The red, green, and blue boxes correspond to the time periods of 2005 to 2012, 2014 to 2016, and 2016 to 2020, respectively; The isopleths in Fig. 2b represent OHCA"

Fig. 3

The corresponding distributions of ocean heat content anomaly time series (a—c) and TGN (d), MMWS (e), and PDI (f) time series at different depths. The black solid line in (d—f) represents the average value of the corresponding parameter, and the black dashed line represents the annual average of extreme values. Red asterisks indicate the months within each year in which the OHCA reaches its minimum and the typhoon parameters reach their maximum. The red, green, and blue boxes correspond to the time periods of 2005 to 2012, 2014 to 2016, and 2016 to 2020, respectively"

Fig. 4

Lagged spatial distribution of ocean heat uptake anomaly (OHUA) at different depths and corresponding typhoon parameters. (a1), (b1), and (c1) are the relative distributions of OHUA with a lag of one month compared to typhoon genesis number (TGN), mean maximum wind speed (MMWS), and power dissipation index (PDI) at 0 to 300 m, respectively; (a2), (b2), and (c2) are the relative distributions of OHUA with a lag of 3 months compared to TGN, MMWS, and PDI at 300 to 700 m, respectively; (a3), (b3), and (c3) are the relative distributions of thermal OHUA with a lag of 6 months compared to TGN, MMWS, and PDI at 700 to 2000 m, respectively"

Fig. 5

Distribution of lagged correlation coefficients between typhoon parameters and ocean heat uptake anomaly (OHUA) at different depths: a1, b1, c1: from the surface to the mixed layer depth, with typhoon parameters lagging OHUA by 1 month; a2, b2, c2: from the mixed layer to 300 m depth, with typhoon parameters lagging OHUA by 2 months; a3, b3, c3: at depths between 300 and 700 m, with typhoon parameters lagging OHUA by 3 months; a4, b4, c4: at depths between 700 and 2000 m, with typhoon parameters lagging OHUA by 6 months. The first column is TGN, the second column is MMWS and the third column is PDI"

Fig. 6

Spatial distribution of Richardson number (RI) averaged over multiple years and months at different depths corresponding to the peak typhoon months. a1 to a4 represent the RI values within the mixed layer, from the mixed layer to 300 m, from 300 m to 700 m, and from 700 m to 2000 m in August, respectively; b1 to b4 represent the RI values within the mixed layer, from the mixed layer to 300 m, from 300 m to 700 m,, and from 700 m to 2000 m in September, respectively"

Fig. 7

Ocean heat uptake anomaly (OHUA) at different depths along the typhoon path in August and September. (a1) to (a3), (b1) to (b3), and (c1) to (c3) are the OHUA values that lag by 0, 1, and 2 months within the mixed layer, from the mixed layer to 300 m, and from 300 m to 700 m, respectively"

Fig. 8

Relative scatter probability density distribution of ocean heat uptake anomaly (OHUA) versus typhoon parameters at different depths during the typhoon season (July to October). (a1) to (a4) are the relative distribution of OHUA and typhoon generation quantities within the mixed layer, from the mixed layer to 300 m, from 300 m to 700 m, and from 700 m to 2000 m, respectively; (b1) to (b4) are similar to (a1) to (a4), except that the typhoon parameter is the maximum wind speed; (c1) to (c4) are similar to (a1) to (a4), except that the typhoon parameter is the energy dissipation index. The coloring in the figure represents statistical probability density, the black circle represents the high probability density distribution range (above average), and the purple dashed line represents the zero contour of OHUA"

Tab. 1

Lag correlation coefficients between ocean heat uptake anomaly (OHUA) at different depths and typhoon parameters"

Fig. 9

Frequency statistics of 0 to 2000 m ocean heat content anomaly (OHCA) and typhoon parameters under different climatic conditions in the Northwest Pacific from 2004 to 2023. (a) to (d) show the frequency statistics of OHCA, OHUA, TGN, MMWS, and PDI, respectively. The red solid line in the figure represents the temperature anomaly value and the red and blue shadows represent El Niño and La Niña events, respectively"

Fig. 10

Variations in ocean heat content anomaly (OHCA) along typhoon tracks in various water layers under different climatic conditions in the Northwest Pacific from 2004 to 2023. (a1) to (a3) and (b1) to (b3) represent OHCA changes within the mixed layer depth, from the mixed layer to 300 m, and from 300 m to 700 m along typhoon tracks during El Niño and La Niña events, respectively. The black dashed line in the figure represents 150°E"

Fig. 11

Spatial distribution of Richardson number (RI) under different climatic conditions in the Northwest Pacific from 2004 to 2023. (a1) to (a3) and (b1) to (b3) represent the average RI distribution within the mixed layer depth, from the mixed layer to 300 m, and from 300 m to 700 m during El Niño and La Niña events, respectively. The black dashed circle in the figure represents the distribution range of low RI values, and the black dashed line represents 150°E"