patrickbdevaney/mia9 · Datasets at Hugging Face

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an indicator that the detected MHWs over these areas are characterized by unusual high
SST levels (see Section 3.4). The open waters of the Straits of Florida were characterized
by high 90th percentiles during winter and spring but lower levels than the WFS and EFS
areas during the summer months, due to the FC evolution that controls the distribution of
physical properties over the Straits (see Section 4.2). Two distinctive seasonal changes are
detected during the annual cycle: one during June, when both 10th and 90th percentiles
revealed a strong increase over the entire study domain, and a second in November, when
both metrics showed significant reductions.
the positive Sens Slope was smaller (0.05 C/decade) and not statistically significant (pvalue
> 0.01). A year of very distinctive behavior was 2010, when although the colder air conditions prevailed (<24 °C; Figure 3a) and the lowest minimum SST levels also occurred (Figure 3c), the 99th percentile was relatively high (30.7°; Figure 3b) resulting in the largest
annual variance among all years (>9 °C; Figure 3d). According to Soto et al. (2011) findings, 2010 can be characterized as a year of high risk on coral losses. The cold January of
2010 (Colella et al., 2012) affected the water temperature levels and reduced the mean annual levels, but very high SST levels also occurred during the summer period, increasing
the 99th percentile annual variance. It is concluded that the observed general increasing
trend is mainly related to the summer maximum values and less related to increases during the winter periods. For most of the years, the variance of the annual values ranges
between 5 °C and 6 °C, with a very small increasing trend throughout the entire period
(0.05 °C/decade; Figure 3d). Even though the variance showed a small increasing trend,
indicating larger seasonal differences, the annual variance is relatively small (<5 °C) during the last decade (2012–2021), when all winter and summer levels were high, confirming
the general warming of the ocean; the highest minimum temperatures were observed during the same period (Figure 3c).
Figure 3. Annual variability (continuous lines) and trends (dashed lines) of: (a) the mean sea surface
temperature (SST; °C) and air temperature (Air Temp; °C); (b) the 99th percentile of SST; (c) the
minimum (min) SST; and (d) the variance, averaged over the entire study domain (Figure 1) for the
period 1982–2021. The Sen’s Slope and coefficient of determination (R2
) for each trend are presented.
The asterisk (*) indicates that the hypothesis that the trend is statistically significant is true (99% MK
test of statistically significant trend: pvalue < 0.01).
Figure 3. Annual variability (continuous lines) and trends (dashed lines) of: (a) the mean sea surface
temperature (SST; ◦C) and air temperature (Air Temp; ◦C); (b) the 99th percentile of SST; (c) the
minimum (min) SST; and (d) the variance, averaged over the entire study domain (Figure 1) for the
period 1982–2021. The Sen’s Slope and coefficient of determination (R2
) for each trend are presented.
The asterisk (*) indicates that the hypothesis that the trend is statistically significant is true (99% MK
test of statistically significant trend: pvalue < 0.01).
We focus on the coastal, island and shelf (WFS and EFS; <300 m) areas over the South
Florida region and estimate the spatial variability of the interannual trends and maximum
levels of the SST (Figure 5). The warmest coastal areas (>26 ◦C) were detected over the
EFS (south of West Palm Beach), south of the Florida Keys and over the southwestern
WFS (Figure 5a). The broader Tampa area in the West and coasts north of the West Palm
Beach in the East showed the lowest mean values (<24.5 ◦C), while relatively low levels
(~25 ◦C) were also detected in the West between Fort Myers and Naples. The highest
99th percentiles that represent the maximum SST levels, were computed for the entire
southwestern Florida coast, the Florida Keys, and the Biscayne Bay (>31 ◦C; Figure 5b);
values over 32.5◦ were observed in Florida Bay, inside the bay of Fort Myers and north of
the Florida Keys. The broader WFS, the Dry Tortugas, the area south of the Florida Keys
and the EFS showed 99th percentiles around 30.7 ◦C, while the lowest maximum levels
occurred north of West Palm Beach (<30 ◦C). The general trend of the mean SST for the
broader region was 0.19 ◦C/decade (Figure 3) mainly over the western WFS and in the
coastal region south of the Florida Keys (Figure 5c), where it was statistically significant
(99%; Figure 5d). The coastal areas of western Florida, the northern Florida Keys, and
the northern EFS revealed the lowest Sen’s Slopes (<0.14 ◦C/decade; Figure 5c); the areas
north of West Palm Beach, Naples, south of Fort Myers, and Tampa also showed pvalues
higher than 5% indicating the weak statistical significance of the trends based on the
Water 2022, 14, 3840 10 of 28
95% MK trend test (Figure 5d). The other coastal regions that exhibited weak trends,
although they revealed small Sen’s Slopes, had pvalues lower than 5% (areas inside the
95% contour; red line in Figure 5d), confirming the statistical significance of the respective
trends. Biscayne Bay showed Sen’s Slopes around 0.11 ◦C/decade, while the trend of the
ocean side of Miami Beach was stronger (0.14 ◦C/decade) and more statistically significant
(pvalue < 0.01). Stronger trends were computed in Florida Bay (>0.17 ◦C/decade), although
the trend was milder (<0.13 ◦C/decade) at the rest of the southern WFS (north of Florida
Keys). North of Key West, the computed weak trends were also associated with very
high pvalues, indicating negligible interannual trend over the 1982–2021 period. The spatial
variability of the SST trends is also projected in the distribution of the MHW occurrence
frequencies and interannual trends (see Section 3.4).
sidered unseasonably warm. The monthly 90th percentile was used as the temperature
climatology (threshold) for the MHW computation (see Section 3.4). The colder waters
have been detected over the entire WFS between January and March (<17 °C; Figure 4),
while very low SST also occurred along the western Florida coast in December. Over the
same areas and months, the 90th percentiles were relatively low (<24 °C) revealing their
lowest values between the coastal region of Tampa (28° N) and Fort Myers (26° N). The
highest 10th and 90th percentile values were computed during July-September for the entire study domain; especially the 10th percentiles were homogenously distributed over all
areas. The maximum 90th percentiles were computed over the southern WFS (>31 °C),
and especially along the northern coasts of the Florida Keys during the summer months
and early fall. The high 90th percentiles are an indicator that the detected MHWs over
these areas are characterized by unusual high SST levels (see Section 3.4). The open waters
of the Straits of Florida were characterized by high 90th percentiles during winter and
spring but lower levels than the WFS and EFS areas during the summer months, due to
the FC evolution that controls the distribution of physical properties over the Straits (see
Section 4.2). Two distinctive seasonal changes are detected during the annual cycle: one
during June, when both 10th and 90th percentiles revealed a strong increase over the entire study domain, and a second in November, when both metrics showed significant reductions.
Figure 4. Horizontal distribution of the monthly 10th (left panels) and 90th (right panels) percentiles of SST derived from the daily satellite data over the 1982–2021 period. The monthly horizontal
levels of 90th percentiles represent the monthly climatological baseline of the Marine Heat Wave
(MHW) estimation.
Figure 4. Horizontal distribution of the monthly 10th (left panels) and 90th (right panels) percentiles
of SST derived from the daily satellite data over the 1982–2021 period. The monthly horizontal
levels of 90th percentiles represent the monthly climatological baseline of the Marine Heat Wave
(MHW) estimation.
3.4. Formation of Marine Heat Waves
3.4.1. Spatial Variability and General Trends
The formation of MHWs was computed and analyzed for the entire study region,
and for the whole time period. Both the annual number of MHW events and their total
annual durations (days), which were averaged over the South Florida domain, revealed an
increasing trend during the 40-year period and are statistically significant (pvalue < 0.01;
Figure 6a). The increase of the total annual MHW days was 7.4 days/decade, and the
respective increase of the MHW events was 0.75 events/decade. Three large peaks were
computed in 2015, 2019, and 2020, respectively, with more than 8 MHWs lasting around
70 to 110 days in total, constituting the high peaks of the mean SST values presented in
Figure 3a. The prolonged period of low SST levels reported during the 2004–2013 decade
(Figure 3a) agrees with the low number of MHWs events (<4) and days (<40) (Figure 6a).
However, the period with the lowest SST levels in 2010 does not coincide with the lowest
MHW events since the reduced SST were mainly associated with the very cold waters of

an indicator that the detected MHWs over these areas are characterized by unusual high

SST levels (see Section 3.4). The open waters of the Straits of Florida were characterized

by high 90th percentiles during winter and spring but lower levels than the WFS and EFS

areas during the summer months, due to the FC evolution that controls the distribution of

physical properties over the Straits (see Section 4.2). Two distinctive seasonal changes are

detected during the annual cycle: one during June, when both 10th and 90th percentiles

revealed a strong increase over the entire study domain, and a second in November, when

both metrics showed significant reductions.

the positive Sens Slope was smaller (0.05 C/decade) and not statistically significant (pvalue

> 0.01). A year of very distinctive behavior was 2010, when although the colder air conditions prevailed (<24 °C; Figure 3a) and the lowest minimum SST levels also occurred (Figure 3c), the 99th percentile was relatively high (30.7°; Figure 3b) resulting in the largest

annual variance among all years (>9 °C; Figure 3d). According to Soto et al. (2011) findings, 2010 can be characterized as a year of high risk on coral losses. The cold January of

2010 (Colella et al., 2012) affected the water temperature levels and reduced the mean annual levels, but very high SST levels also occurred during the summer period, increasing

the 99th percentile annual variance. It is concluded that the observed general increasing

trend is mainly related to the summer maximum values and less related to increases during the winter periods. For most of the years, the variance of the annual values ranges

between 5 °C and 6 °C, with a very small increasing trend throughout the entire period

(0.05 °C/decade; Figure 3d). Even though the variance showed a small increasing trend,

indicating larger seasonal differences, the annual variance is relatively small (<5 °C) during the last decade (2012–2021), when all winter and summer levels were high, confirming

the general warming of the ocean; the highest minimum temperatures were observed during the same period (Figure 3c).

Figure 3. Annual variability (continuous lines) and trends (dashed lines) of: (a) the mean sea surface

temperature (SST; °C) and air temperature (Air Temp; °C); (b) the 99th percentile of SST; (c) the

minimum (min) SST; and (d) the variance, averaged over the entire study domain (Figure 1) for the

period 1982–2021. The Sen’s Slope and coefficient of determination (R2

) for each trend are presented.

The asterisk (*) indicates that the hypothesis that the trend is statistically significant is true (99% MK

test of statistically significant trend: pvalue < 0.01).

Figure 3. Annual variability (continuous lines) and trends (dashed lines) of: (a) the mean sea surface

temperature (SST; ◦C) and air temperature (Air Temp; ◦C); (b) the 99th percentile of SST; (c) the

minimum (min) SST; and (d) the variance, averaged over the entire study domain (Figure 1) for the

period 1982–2021. The Sen’s Slope and coefficient of determination (R2

) for each trend are presented.

The asterisk (*) indicates that the hypothesis that the trend is statistically significant is true (99% MK

test of statistically significant trend: pvalue < 0.01).

We focus on the coastal, island and shelf (WFS and EFS; <300 m) areas over the South

Florida region and estimate the spatial variability of the interannual trends and maximum

levels of the SST (Figure 5). The warmest coastal areas (>26 ◦C) were detected over the

EFS (south of West Palm Beach), south of the Florida Keys and over the southwestern

WFS (Figure 5a). The broader Tampa area in the West and coasts north of the West Palm

Beach in the East showed the lowest mean values (<24.5 ◦C), while relatively low levels

(~25 ◦C) were also detected in the West between Fort Myers and Naples. The highest

99th percentiles that represent the maximum SST levels, were computed for the entire

southwestern Florida coast, the Florida Keys, and the Biscayne Bay (>31 ◦C; Figure 5b);

values over 32.5◦ were observed in Florida Bay, inside the bay of Fort Myers and north of

the Florida Keys. The broader WFS, the Dry Tortugas, the area south of the Florida Keys

and the EFS showed 99th percentiles around 30.7 ◦C, while the lowest maximum levels

occurred north of West Palm Beach (<30 ◦C). The general trend of the mean SST for the

broader region was 0.19 ◦C/decade (Figure 3) mainly over the western WFS and in the

coastal region south of the Florida Keys (Figure 5c), where it was statistically significant

(99%; Figure 5d). The coastal areas of western Florida, the northern Florida Keys, and

the northern EFS revealed the lowest Sen’s Slopes (<0.14 ◦C/decade; Figure 5c); the areas

north of West Palm Beach, Naples, south of Fort Myers, and Tampa also showed pvalues

higher than 5% indicating the weak statistical significance of the trends based on the

Water 2022, 14, 3840 10 of 28

95% MK trend test (Figure 5d). The other coastal regions that exhibited weak trends,

although they revealed small Sen’s Slopes, had pvalues lower than 5% (areas inside the

95% contour; red line in Figure 5d), confirming the statistical significance of the respective

trends. Biscayne Bay showed Sen’s Slopes around 0.11 ◦C/decade, while the trend of the

ocean side of Miami Beach was stronger (0.14 ◦C/decade) and more statistically significant

(pvalue < 0.01). Stronger trends were computed in Florida Bay (>0.17 ◦C/decade), although

the trend was milder (<0.13 ◦C/decade) at the rest of the southern WFS (north of Florida

Keys). North of Key West, the computed weak trends were also associated with very

high pvalues, indicating negligible interannual trend over the 1982–2021 period. The spatial

variability of the SST trends is also projected in the distribution of the MHW occurrence

frequencies and interannual trends (see Section 3.4).

sidered unseasonably warm. The monthly 90th percentile was used as the temperature

climatology (threshold) for the MHW computation (see Section 3.4). The colder waters

have been detected over the entire WFS between January and March (<17 °C; Figure 4),

while very low SST also occurred along the western Florida coast in December. Over the

same areas and months, the 90th percentiles were relatively low (<24 °C) revealing their

lowest values between the coastal region of Tampa (28° N) and Fort Myers (26° N). The

highest 10th and 90th percentile values were computed during July-September for the entire study domain; especially the 10th percentiles were homogenously distributed over all

areas. The maximum 90th percentiles were computed over the southern WFS (>31 °C),

and especially along the northern coasts of the Florida Keys during the summer months

and early fall. The high 90th percentiles are an indicator that the detected MHWs over

these areas are characterized by unusual high SST levels (see Section 3.4). The open waters

of the Straits of Florida were characterized by high 90th percentiles during winter and

spring but lower levels than the WFS and EFS areas during the summer months, due to

the FC evolution that controls the distribution of physical properties over the Straits (see

Section 4.2). Two distinctive seasonal changes are detected during the annual cycle: one

during June, when both 10th and 90th percentiles revealed a strong increase over the entire study domain, and a second in November, when both metrics showed significant reductions.

Figure 4. Horizontal distribution of the monthly 10th (left panels) and 90th (right panels) percentiles of SST derived from the daily satellite data over the 1982–2021 period. The monthly horizontal

levels of 90th percentiles represent the monthly climatological baseline of the Marine Heat Wave

(MHW) estimation.

Figure 4. Horizontal distribution of the monthly 10th (left panels) and 90th (right panels) percentiles

of SST derived from the daily satellite data over the 1982–2021 period. The monthly horizontal

levels of 90th percentiles represent the monthly climatological baseline of the Marine Heat Wave

(MHW) estimation.

3.4. Formation of Marine Heat Waves

3.4.1. Spatial Variability and General Trends

The formation of MHWs was computed and analyzed for the entire study region,

and for the whole time period. Both the annual number of MHW events and their total

annual durations (days), which were averaged over the South Florida domain, revealed an

increasing trend during the 40-year period and are statistically significant (pvalue < 0.01;

Figure 6a). The increase of the total annual MHW days was 7.4 days/decade, and the

respective increase of the MHW events was 0.75 events/decade. Three large peaks were

computed in 2015, 2019, and 2020, respectively, with more than 8 MHWs lasting around

70 to 110 days in total, constituting the high peaks of the mean SST values presented in

Figure 3a. The prolonged period of low SST levels reported during the 2004–2013 decade

(Figure 3a) agrees with the low number of MHWs events (<4) and days (<40) (Figure 6a).

However, the period with the lowest SST levels in 2010 does not coincide with the lowest

MHW events since the reduced SST were mainly associated with the very cold waters of