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Gulf of Maine Warming Update: Spring 2022

Announcements | Jul 1, 2022

Over the past decade, scientists have led a body of research that highlights the rapid pace of warming in the Gulf of Maine. To help keep you informed, we share seasonal and annual updates about conditions in the Gulf of Maine.

Read on for an inside look at what we've learned in our Spring 2022 Gulf of Maine warming update.

A graphic that resembles a stream plot has blue colors on the top, green in the middle, and reddish colors on the bottom.

About the Updates:

Over the past decade, scientists at the Gulf of Maine Research Institute have led a body of research that highlights the rapid pace of warming in the Gulf of Maine. To keep you informed, we share seasonal updates about sea surface temperature (SST) conditions in the Gulf of Maine.

Note About the Data: The figures in this report are creating using remotely sensed satellite data as part of publicly funded research efforts. We obtained satellite-derived SST data from NOAA’s National Center for Environmental Information (NCEI), with all maps and figures displaying NOAA’s Optimum Interpolation Sea Surface Temperature Data.

Note on Preliminary Data: This dataset has a 2-week latency period, during which values may change due to quality control measures. Any data within 14 days of the publication date may be subject to change.

The Gulf of Maine Region

For analyses like these, it is important to be clear about the spatial extent that “defines” the Gulf of Maine (Fig. 1), as different borders could produce different numbers. The spatial extent we use as the “Gulf of Maine” is displayed below. This area is consistent with previous reports and publications produced by GMRI.

This seasonal report presents an analysis of SST for Spring 2022 (March 1 through May 31).

This is a map of the Gulf of Maine study area for our warming updates, showing contours and depth, and labeled areas.
Spatial domain used for Gulf of Maine SST analyses.

Highlights

The average SST for the Gulf of Maine during spring 2022 was 45.34°F, which is 2.87°F above the long-term (1982 – 2011) average of 42.47°F.

It was the 3rd hottest spring on record for the period of 1982 – 2022.

Weekly Temperatures

In the below table – which shows observed, long-term average, and departures from the long-term average SST – we can see how the SST for each week this spring compares to a 30-year baseline period (note, climatological averages are calculated with data spanning 1982 through 2011).

Table 1. Observed, climatological average, and deviation from the climatological average (i.e., temperature anomaly) for SST at a weekly resolution in the Gulf of Maine during spring 2022 (defined as March 1 through May 31).
Table 1. Observed, climatological average, and deviation from the climatological average (i.e., temperature anomaly) for SST at a weekly resolution in the Gulf of Maine during spring 2022 (defined as March 1 through May 31).

Monthly Statistics

Looking at monthly averages (as opposed to week-by-week conditions), we see that May showed the largest deviation from the long-term average, with an average SST anomaly of 3.40°F (Table 2). Each month was 2.4°F or more above the 1982 – 2011 average.

Table 2. Observed, climatological average, and deviation from the climatological average (i.e., temperature anomaly) for SST at a monthly resolution in the Gulf of Maine during spring 2022 (defined as March 1 through May 31).
Table 2. Observed, climatological average, and deviation from the climatological average (i.e., temperature anomaly) for SST at a monthly resolution in the Gulf of Maine during spring 2022 (defined as March 1 through May 31).

Seasonal Trends and Anomalies in Context

SSTs warming at a rate of .51°F per decade reflect a clear long-term increase in average spring temperatures (Fig. 2). Seasonal averages and daily temperatures also generally remained above the 30-year (1982 – 2011) climatology.

Fig. 2. Average annual spring SSTs in the Gulf of Maine from 1982 through 2022. The solid red line indicates the trend for the full time series.
Fig. 2. Average annual spring SSTs in the Gulf of Maine from 1982 through 2022. The solid red line indicates the trend for the full time series.

This period of faster warming is part of what appears to be a distinct regime shift in the Gulf of Maine. The drivers of this (e.g., recent shifts in the influence of the Gulf Stream, persistent modes of natural variability, and the possible onset of a weakening in the Atlantic Meridional Overturning Circulation) have been well-documented in the peer-reviewed literature, including through research by GMRI scientists.

How Does 2022 Compare?

2022 was among the warmest springs seen in the Gulf of Maine during this 40+ year period. When compared against all previous springs for which we have reliable satellite data (i.e., back to 1982), this year ranks #3 for hottest spring on record.

Fig. 3. An illustration of where spring 2022 ranks among the top top five warmest spring seasons on record in the Gulf of Maine. Also notable is the fact that all five warmest spring seasons on record have occurred in the last ten years.
Fig. 3. An illustration of where spring 2022 ranks among the top top five warmest spring seasons on record in the Gulf of Maine. Also notable is the fact that all five warmest spring seasons on record have occurred in the last ten years.

Marine Heatwave Conditions

The most commonly used definition of a “marine heatwave” (MHW) is when daily average SSTs exceed the 90th percentile of a climatological (i.e., 30 year) average for at least 5 consecutive days. Successive heatwaves with temporal gaps of 2 days or less are considered part of the same event.

Using this broadly accepted definition, the Gulf of Maine has experienced MHW conditions through spring 2022. A brief reprieve in mid-May lasted less than two days, so it did not constitute a break in the heatwave event (Fig. 4).

Fig. 4. A timeseries of marine heatwave (MHW) conditions in the Gulf of Maine extending from January 2022 through May 31. The dashed black line represents the long-term (i.e., 1982 – 2011) average SST for a given day in the Gulf of Maine; the dotted red line indicates a threshold above which the Gulf of Maine is in a MHW status; light blue shading represents daily SST values with the red shading illustrating when those daily SST values are part of a MHW event.
Fig. 4. A timeseries of marine heatwave (MHW) conditions in the Gulf of Maine extending from January 2022 through May 31. The dashed black line represents the long-term (i.e., 1982 – 2011) average SST for a given day in the Gulf of Maine; the dotted red line indicates a threshold above which the Gulf of Maine is in a MHW status; light blue shading represents daily SST values with the red shading illustrating when those daily SST values are part of a MHW event.

Presenting SST conditions in terms of anomalies (Fig. 5 below) as opposed to absolute values (Fig. 4 above) illustrates in greater detail the magnitude of MHW conditions throughout the spring season. The most extreme anomalies this spring occurred in the second half of May, with temperatures exceeding 5°F above the climatological average.

Fig. 5. A timeseries of daily average SST anomalies in the Gulf of Maine (solid red line) compared to marine heatwave (MHW) conditions (dashed orange line) in the Gulf of Maine for the period January 1 through May 31, 2022.
Fig. 5. A timeseries of daily average SST anomalies in the Gulf of Maine (solid red line) compared to marine heatwave (MHW) conditions (dashed orange line) in the Gulf of Maine for the period January 1 through May 31, 2022.

Looking at the full record of daily SST anomalies in the Gulf of Maine (Fig. 6 below), the distinct thermal regime shift beginning around 2010 is evident. Indeed, since 2012, the Gulf of Maine has experienced far more persistent MHW conditions (indicated by solid black lines) than at any other point in the satellite record.

Fig. 6. Heat map of daily sea surface temperature anomalies from the beginning of 1982 through the middle of 2022. Not only do more large warm anomalies (darker reds) appear more frequently in recent years, but the frequency and duration of marine heatwave events (black lines) in the Gulf of Maine has become more pronounced in the past decade.
Fig. 6. Heat map of daily sea surface temperature anomalies from the beginning of 1982 through the middle of 2022. Not only do more large warm anomalies (darker reds) appear more frequently in recent years, but the frequency and duration of marine heatwave events (black lines) in the Gulf of Maine has become more pronounced in the past decade.

Spatial Perspective on Monthly & Seasonal SST Anomalies

From a spatial perspective (Fig. 7), the Gulf of Maine and surrounding areas experienced above average SSTs for much of the region during spring 2022, but with particularly warm patches to the south and east of Georges Bank that reached seasonally-averaged anomalies of up to 9.4°F.

Fig. 7. Map of average SST anomalies in spring 2022. The box outlined by the black dashed line denotes the region of study for the analysis. Darker red regions indicate stronger anomalies.
Fig. 7. Map of average SST anomalies in spring 2022. The box outlined by the black dashed line denotes the region of study for the analysis. Darker red regions indicate stronger anomalies.

Average monthly temperature anomalies are displayed below (Fig. 8). The warmest anomalies were concentrated just south of the domain studied in this analysis in March, but by April and May the waters south and east of Georges Bank and near the Northeast Channel were experiencing daily SSTs >8°F warmer than during our climate reference period (1982 – 2011).

Fig. 8. This series of maps shows the average monthly SST temperature anomalies in March, April, and May 2022. The box outlined by the black dashed line denotes the region of study for the analysis. Darker red regions indicate stronger anomalies.
Fig. 8. This series of maps shows the average monthly SST temperature anomalies in March, April, and May 2022. The box outlined by the black dashed line denotes the region of study for the analysis. Darker red regions indicate stronger anomalies.

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