Table 1 List of explanatory variables used in the ordinal logistic regression analysis

1. Depth

Instrument depth [m]

depth

In situ water depth of instrument

2. Background Conditions

Latitude [DD]

lats

Latitude of instrument

Maximum Monthly Mean (MMM) [°C]

MMM_Total

Maximum of monthly mean climatology from entire time series

⁸⁵

MMM

Maximum of monthly mean climatology using data only before and during bleaching event

MMM_4 km

Maximum of monthly mean climatology using 4 km weekly CoRTAD SST data

MMM_Max

Mean of maximum monthly SST from each year in climatological time period

¹⁵

3. Cumulative Thermal Stress

Degree Heating Weeks (DHW) [°C-weeks]

DHW₉₀

Trapezoidal integration of temperatures in excess of MMM+ 1 °C during 90 days preceding a bleaching event

⁸⁵

DHW₃₀

Trapezoidal integration of temperatures in excess of MMM+ 1 °C during 30 days preceding a bleaching event

DHW_4 km

Degree heating week product from 4 km weekly CoRTAD SST data

Cumulative Summer Anomaly (CSA) [°C-days]

CSA_Total

Trapezoidal integration of temperatures in excess of MMM+ 1 °C during all summer periods through entire time series

CSA_Before

Trapezoidal integration of temperatures in excess of MMM+ 1 °C during summer periods before and during a bleaching event

CSA_During

Trapezoidal integration of temperatures in excess of MMM+ 1 °C during summer of bleaching event

4. Acute Thermal Stress

Presence/absence of acute temperature anomaly [binary]

Acute1

Binary value indicating whether any of the daily mean temperatures within 90 days preceeding a bleaching event exceeded MMM+ 1 °C

Acute1_4 km

Acute1 computed using 4 km weekly CoRTAD SST data

Acute2

Binary value indicating whether any of the daily mean temperatures within 90 days preceeding a bleaching event exceeded MMM+ 2 °C

Acute2_4 km

Acute2 computed using 4 km weekly CoRTAD SST data

5. Thermal Trajectory

Type of induced thermal tolerance prior to acute thermal stress, using twice-weekly averaged temperatures [ordinal]

TT

0: No thermal stress (temperatures do not exceed MMM+ 2 °C within 90 days prior to survey date)

1: Protective Trajectory (temperatures exceed MMM, then have a recovery period below MMM for at least 10 days prior to exceeding MMM+ 2 °C)

2: Single Bleaching Trajectory (temperatures exceed both MMM and MMM+ 2 °C without a 10-day recovery period in between)

3: Repetitive Bleaching Trajectory (temperatures exceed MMM+ 2 °C in two peaks separated by 9 days)

³⁹

6. Heating Rate

Rate of spring-summer temperature change [°C/day]

ROTC_SS

Mean rate of temperature change during spring and summer of all years

²⁵

ROTC_90-4 km

Mean rate of temperature change during 90 days preceding a bleaching event using CoRTAD SST data

ROTC_{SS-4  km}

Mean rate of temperature change during spring and summer of all years using CoRTAD SST data

7. High-Frequency Temperature Variability

Daily Temperature Range (DTR) [°C]

DTR_Total

Mean DTR over entire time series

DTR_SS

Mean DTR of all spring and summer periods

DTR_FW

Mean DTR of all fall and winter periods

DTR₉₀

Mean DTR over 90 days preceding a bleaching event

DTR₃₀

Mean DTR over 30 days preceding a bleaching event

8. DTR Distribution Shape

Measure of shape of distribution of all DTR values w/in a time series [−]

kurtosis

Kurtosis of full time series of DTR values

skewness

Skewness of full time series of DTR values