patrickbdevaney/mia9 · Datasets at Hugging Face

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than 110 events during the 40-year period (Figure 7c). Although fewer events usually
formed over the northern parts of the WFS (2–2.5 events/year and less than 100 in total
for 40 years), their duration was longer and therefore the total annual duration over the
shelf was homogenously distributed between 24 to 30 days/year (Figure 7b) and more
than 1000 days over the 1982–2021 period (Figure 7d). The Straits of Florida, where the
warmer waters of the FC prevail, are characterized by fewer events with smaller durations
due to the constant high 90th percentile levels that were used as thresholds in the MHW
detection. However, the meandering of the FC and its approach toward the Florida coasts
plays an important role on both local circulation over the coastal region and the distribution
of the physical properties (see Section 4.2). The coastal region of the Bahamas can also be
considered as a “hot spot” for MHWs with high number of events (>100; Figure 7c) and
long durations (>1000 days; Figure 7d) during the 1982–2021 period.
3.4.2. Variability of MHWs at Coastal and Urban Areas
Ten coastal areas of South Florida with urban and environmental interest (insert maps
in Figure 8) were chosen to further analyze the formation and variability of MHW events
during the 1982–2021 period. The mean annual number and duration of events, and the
mean annual SST for each coastal area are presented in Figure 8. The respective Sen’s Slopes
of all 40-year trends and their statistical significance tests (pvalues) are presented in Table 2.
The broader Miami coastal area is investigated focusing on two sub-regions: the enclosed
basin of Biscayne Bay (Figure 8c), which is relatively protected from ocean influence, and
Water 2022, 14, 3840 13 of 28
Miami Beach (Figure 8b), which is more exposed to offshore dynamics of the northern
Straits of Florida. Although Biscayne Bay showed a larger number of events over the entire
study period (Figure 7c), the increasing trend of Miami Beach is steeper (1.1 events/decade;
Table 2), resulting in the formation of more events, especially during the last seven years
(Figure 8b). Respectively, the Sen’s Slope of the duration is 10 days/decade for Miami
Beach and 7.2 days/decade for Biscayne Bay. Biscayne Bay also showed a smaller SST trend
(0.1 ◦C/decade), in agreement with the spatial distribution of trends presented in Figure 5c,
compared to the Miami Beach trends (0.15 ◦C/decade; Table 2). All trends are statistically
significant but the Biscayne Bay pvalues were higher (Table 2; Figure 5d), especially for the
SST trend (pvalue = 0.021 > 0.01), thus featuring an overall less significant trend. In 2019 and
2020, more than 9 events occurred in the coastal area of Miami Beach with 100 days total
duration (Figure 8b), while less than 8 events with total duration around 75 days occurred
in Biscayne Bay (Figure 8c). Biscayne Bay had shown more frequent MHWs until 2010 in
comparison to Miami Beach, where several years without any formations were detected
during the same period (e.g., 1983–1985, 1988, 1996, 2001, 2008; Figure 8b). Miami Beach is
actually characterized by stronger interannual variations, showing years with both larger
and smaller number of events, in comparison to the enclosed Biscayne Bay. The offshore
ocean dynamics that contribute to this variability are discussed in Section 4.2.
Water 2022, 14, x FOR PEER REVIEW 14 of 31
waters of the FC prevail, are characterized by fewer events with smaller durations due to
the constant high 90th percentile levels that were used as thresholds in the MHW detection. However, the meandering of the FC and its approach toward the Florida coasts plays
an important role on both local circulation over the coastal region and the distribution of
the physical properties (see Section 4.2). The coastal region of the Bahamas can also be
considered as a “hot spot” for MHWs with high number of events (>100; Figure 7c) and
long durations (>1000 days; Figure 7d) during the 1982–2021 period.
Figure 7. (a) Mean annual number, (b) mean annual duration (days), (c) total number, and (d) total
duration (days) of MHW events derived from the satellite observations of the 1982–2021 period.
3.4.2. Variability of MHWs at Coastal and Urban Areas
Ten coastal areas of South Florida with urban and environmental interest (insert
maps in Figure 8) were chosen to further analyze the formation and variability of MHW
events during the 1982–2021 period. The mean annual number and duration of events,
and the mean annual SST for each coastal area are presented in Figure 8. The respective
Sen’sSlopesofall40yeartrendsandtheirstatisticalsignificancetests(pl)arepreFigure 7. (a) Mean annual number, (b) mean annual duration (days), (c) total number, and (d) total
duration (days) of MHW events derived from the satellite observations of the 1982–2021 period.
Water 2022, 14, 3840 14 of 28 North Key West 4.6 0.0486 0.6 0.022 0.14 0.036
South Key West 7.5 0.0007 0.8 0.0008 0.18 <0.0001
Dry Tortugas 7.6 0.0011 0.8 0.0011 0.18 <0.0001
Fort Myers 4.6 0.0088 0.5 0.0053 0.14 0.045
Tampa 4.9 0.0006 0.5 0.0003 0.12 0.021
Figure 8. Interannual variability of annual mean number (red solid line), duration (days; black solid
line) of MHW events, the mean annual SST (°C; blue solid line) over (a) West Palm Beach, (b) Miami
Beach, (c) Biscayne Bay, (d) Key Largo, (e) Marathon, (f) North Key West, (g) South Key West, (h)
Dry Tortugas, (i) Fort Myers, and (j) Tampa from 1982 to 2021. The insert maps show the satellite
grid points used for the computation over each area. The respective linear trends are also indicated
with dashed lines.
Different trends were computed between the north and south coastal areas of the
Florida Keys. Although the northern coasts of the Florida Keys (southern WFS) summed
more events during the entire study period (Figure 7c), showing larger annual numbers
of MHWs especially before 2008, the general Sen’s Slopes are weaker in the North Key
Figure 8. Interannual variability of annual mean number (red solid line), duration (days; black solid
line) of MHW events, the mean annual SST (◦C; blue solid line) over (a) West Palm Beach, (b) Miami
Beach, (c) Biscayne Bay, (d) Key Largo, (e) Marathon, (f) North Key West, (g) South Key West, (h) Dry
Tortugas, (i) Fort Myers, and (j) Tampa from 1982 to 2021. The insert maps show the satellite grid
points used for the computation over each area. The respective linear trends are also indicated with
dashed lines.
The northern area of West Palm Beach showed weaker trends (Table 2; Figure 8a)
of the MHWs number (0.7 events/decade) and duration (5.6 days/decade). The largest
number of events was detected in 2019 and 2020 (>6; Figure 8a) when the highest mean
annual SST was also occurred (27.5 ◦C). Generally, the total annual duration ranged below
40 days throughout the entire study period. The broader area of the northern EFS, where
West Palm Beach is located, showed very low 99th percentiles of SST (Figure 5b) with
statistically insignificant SST trends (Figure 5c,d). Even weaker trends were computed
for Tampa (0.5 events/decade, 4.9 days/decade and 0.12 ◦C/decade) and Fort Myers
(0.5 events/decade, 4.6 days/decade and 0.14 ◦C/decade), located at the coastal area of
WFS (Table 2). Especially in Fort Myers, the pvalues were the highest among all coastal areas,
showing statistically insignificant trend for the mean SST, based on the 99% MK trend
Water 2022, 14, 3840 15 of 28
test (pvalue = 0.045). The lowest number of events with small durations were observed
at Tampa, where the highest mean annual number of MHWs, averaged over the Tampa
coastal area grid points, was slightly over 4 events in 2020. These small MHW levels and
weak trends are mainly related to the domination of colder waters detected from December
to March and the very low SST that were measured along the western Florida coast, where
the 90th percentiles revealed their lowest values between the coastal region of Tampa and
Fort Myers (Figure 4).
Table 2. Sen’s Slope (days/decade and events/decade) and pvalues (test of statistically significant
trend) derived from the MK trend test representing the statistical significance of each trend for the
Mean Annual Duration and the Mean Annual Number of Marine Heat Wave (MHW) events, and the
Mean Annual Sea Surface Temperature (SST) for the 10 coastal areas presented in Figure 8.
Coastal Area

than 110 events during the 40-year period (Figure 7c). Although fewer events usually

formed over the northern parts of the WFS (2–2.5 events/year and less than 100 in total

for 40 years), their duration was longer and therefore the total annual duration over the

shelf was homogenously distributed between 24 to 30 days/year (Figure 7b) and more

than 1000 days over the 1982–2021 period (Figure 7d). The Straits of Florida, where the

warmer waters of the FC prevail, are characterized by fewer events with smaller durations

due to the constant high 90th percentile levels that were used as thresholds in the MHW

detection. However, the meandering of the FC and its approach toward the Florida coasts

plays an important role on both local circulation over the coastal region and the distribution

of the physical properties (see Section 4.2). The coastal region of the Bahamas can also be

considered as a “hot spot” for MHWs with high number of events (>100; Figure 7c) and

long durations (>1000 days; Figure 7d) during the 1982–2021 period.

3.4.2. Variability of MHWs at Coastal and Urban Areas

Ten coastal areas of South Florida with urban and environmental interest (insert maps

in Figure 8) were chosen to further analyze the formation and variability of MHW events

during the 1982–2021 period. The mean annual number and duration of events, and the

mean annual SST for each coastal area are presented in Figure 8. The respective Sen’s Slopes

of all 40-year trends and their statistical significance tests (pvalues) are presented in Table 2.

The broader Miami coastal area is investigated focusing on two sub-regions: the enclosed

basin of Biscayne Bay (Figure 8c), which is relatively protected from ocean influence, and

Water 2022, 14, 3840 13 of 28

Miami Beach (Figure 8b), which is more exposed to offshore dynamics of the northern

Straits of Florida. Although Biscayne Bay showed a larger number of events over the entire

study period (Figure 7c), the increasing trend of Miami Beach is steeper (1.1 events/decade;

Table 2), resulting in the formation of more events, especially during the last seven years

(Figure 8b). Respectively, the Sen’s Slope of the duration is 10 days/decade for Miami

Beach and 7.2 days/decade for Biscayne Bay. Biscayne Bay also showed a smaller SST trend

(0.1 ◦C/decade), in agreement with the spatial distribution of trends presented in Figure 5c,

compared to the Miami Beach trends (0.15 ◦C/decade; Table 2). All trends are statistically

significant but the Biscayne Bay pvalues were higher (Table 2; Figure 5d), especially for the

SST trend (pvalue = 0.021 > 0.01), thus featuring an overall less significant trend. In 2019 and

2020, more than 9 events occurred in the coastal area of Miami Beach with 100 days total

duration (Figure 8b), while less than 8 events with total duration around 75 days occurred

in Biscayne Bay (Figure 8c). Biscayne Bay had shown more frequent MHWs until 2010 in

comparison to Miami Beach, where several years without any formations were detected

during the same period (e.g., 1983–1985, 1988, 1996, 2001, 2008; Figure 8b). Miami Beach is

actually characterized by stronger interannual variations, showing years with both larger

and smaller number of events, in comparison to the enclosed Biscayne Bay. The offshore

ocean dynamics that contribute to this variability are discussed in Section 4.2.

Water 2022, 14, x FOR PEER REVIEW 14 of 31

waters of the FC prevail, are characterized by fewer events with smaller durations due to

the constant high 90th percentile levels that were used as thresholds in the MHW detection. However, the meandering of the FC and its approach toward the Florida coasts plays

an important role on both local circulation over the coastal region and the distribution of

the physical properties (see Section 4.2). The coastal region of the Bahamas can also be

considered as a “hot spot” for MHWs with high number of events (>100; Figure 7c) and

long durations (>1000 days; Figure 7d) during the 1982–2021 period.

Figure 7. (a) Mean annual number, (b) mean annual duration (days), (c) total number, and (d) total

duration (days) of MHW events derived from the satellite observations of the 1982–2021 period.

3.4.2. Variability of MHWs at Coastal and Urban Areas

Ten coastal areas of South Florida with urban and environmental interest (insert

maps in Figure 8) were chosen to further analyze the formation and variability of MHW

events during the 1982–2021 period. The mean annual number and duration of events,

and the mean annual SST for each coastal area are presented in Figure 8. The respective

Sen’sSlopesofall40yeartrendsandtheirstatisticalsignificancetests(pl)arepreFigure 7. (a) Mean annual number, (b) mean annual duration (days), (c) total number, and (d) total

duration (days) of MHW events derived from the satellite observations of the 1982–2021 period.

Water 2022, 14, 3840 14 of 28 North Key West 4.6 0.0486 0.6 0.022 0.14 0.036

South Key West 7.5 0.0007 0.8 0.0008 0.18 <0.0001

Dry Tortugas 7.6 0.0011 0.8 0.0011 0.18 <0.0001

Fort Myers 4.6 0.0088 0.5 0.0053 0.14 0.045

Tampa 4.9 0.0006 0.5 0.0003 0.12 0.021

Figure 8. Interannual variability of annual mean number (red solid line), duration (days; black solid

line) of MHW events, the mean annual SST (°C; blue solid line) over (a) West Palm Beach, (b) Miami

Beach, (c) Biscayne Bay, (d) Key Largo, (e) Marathon, (f) North Key West, (g) South Key West, (h)

Dry Tortugas, (i) Fort Myers, and (j) Tampa from 1982 to 2021. The insert maps show the satellite

grid points used for the computation over each area. The respective linear trends are also indicated

with dashed lines.

Different trends were computed between the north and south coastal areas of the

Florida Keys. Although the northern coasts of the Florida Keys (southern WFS) summed

more events during the entire study period (Figure 7c), showing larger annual numbers

of MHWs especially before 2008, the general Sen’s Slopes are weaker in the North Key

Figure 8. Interannual variability of annual mean number (red solid line), duration (days; black solid

line) of MHW events, the mean annual SST (◦C; blue solid line) over (a) West Palm Beach, (b) Miami

Beach, (c) Biscayne Bay, (d) Key Largo, (e) Marathon, (f) North Key West, (g) South Key West, (h) Dry

Tortugas, (i) Fort Myers, and (j) Tampa from 1982 to 2021. The insert maps show the satellite grid

points used for the computation over each area. The respective linear trends are also indicated with

dashed lines.

The northern area of West Palm Beach showed weaker trends (Table 2; Figure 8a)

of the MHWs number (0.7 events/decade) and duration (5.6 days/decade). The largest

number of events was detected in 2019 and 2020 (>6; Figure 8a) when the highest mean

annual SST was also occurred (27.5 ◦C). Generally, the total annual duration ranged below

40 days throughout the entire study period. The broader area of the northern EFS, where

West Palm Beach is located, showed very low 99th percentiles of SST (Figure 5b) with

statistically insignificant SST trends (Figure 5c,d). Even weaker trends were computed

for Tampa (0.5 events/decade, 4.9 days/decade and 0.12 ◦C/decade) and Fort Myers

(0.5 events/decade, 4.6 days/decade and 0.14 ◦C/decade), located at the coastal area of

WFS (Table 2). Especially in Fort Myers, the pvalues were the highest among all coastal areas,

showing statistically insignificant trend for the mean SST, based on the 99% MK trend

Water 2022, 14, 3840 15 of 28

test (pvalue = 0.045). The lowest number of events with small durations were observed

at Tampa, where the highest mean annual number of MHWs, averaged over the Tampa

coastal area grid points, was slightly over 4 events in 2020. These small MHW levels and

weak trends are mainly related to the domination of colder waters detected from December

to March and the very low SST that were measured along the western Florida coast, where

the 90th percentiles revealed their lowest values between the coastal region of Tampa and

Fort Myers (Figure 4).

Table 2. Sen’s Slope (days/decade and events/decade) and pvalues (test of statistically significant

trend) derived from the MK trend test representing the statistical significance of each trend for the

Mean Annual Duration and the Mean Annual Number of Marine Heat Wave (MHW) events, and the

Mean Annual Sea Surface Temperature (SST) for the 10 coastal areas presented in Figure 8.

Coastal Area