Overview of the new 2018 analysis and sub-figures check this box to show the analysis and new sub-figures information section
The new PSR-2018 Analysis
The 2018 ICES Plankton Status Report (PSR-2018) no longers uses the traditional "Mackas/WG125 Analysis" (e.g., log10-transformed, ratio-based values and anomalies).
PSR-2018 uses a non-log10-transformed, ratio-based analysis, and both methods apply a seasonal correction in their annual anomaly calculations.
The biggest difference between the methods is that figures and results are now presented in their original units (e.g., number of diatoms per liter vs. a log10 derivative) so the graphical Y-indices can be easily read without first reversing the values from log10 transformation.
The second biggest difference is that the seasonal cycle is no longer "dampened" by log10 geometric math (e.g., a large spring bloom in May now actually visually looks like a large spring bloom in May).
PSR-2018 also incorporates the IGMETS "Time Window" based analysis, allowing the authors and readers to look at the time series in terms of 5-year-incrementally longer and longer time windows (e.g., TW05, TW10, TW15, TW20, ... , TW35).
This allows both shorter (newer) and longer (older) time series to participate in the report and its assorted analyses time windows (e.g., 10-year trends in the North Atlantic vs 30-year trends in the North Atlantic).
The new PSR-2018 Sub-Figure
The left sections of the "standard figure" below (click on that image to see a larger version in a new window) are very similar to the standard figures used in the previous zooplankton and phytoplankton status reports.
The far right section is new, however, and explained farther below.
The LEFT section of the figure above shows the seasonal cycles and variability of the current variable (e.g., Temora longicornis abundance from 1980 to 2016).
The lighter pink-shaded area shows the value-range (by month) where 5% to 95% of the (Temora longicornis) abundance values fall.
The red-shaded area inside of that shows the value-range where 25% to 75% of the values fall.
Finally, the dark red dashed line indicates the median of all values.
The MIDDLE section above shows the annual anomalies and interannual variability of the current variable.
The left Y-axis shows the value of these anomaly bars in the original units (e.g., number per cubic meter). An anomaly bar with a height of "1200" means there were 1200 more (Temora longicornis per cubic meter) that year than the (climatological) average of all values from 1980-2016 (e.g., ClimAvg = 527.8).
The right Y-axis shows the value of these anomalies as a ratio of the anomaly value divided by the long-term average.
A ratio-anomaly value of "2" means that that year's anomaly was 2x larger than the climatological average (ClimAvg).
For example with a ClimAvg of 527.8 (Temora longicornis per cubic meter), a ratio value of "2" in the right-Y-axis corresponds to a value of ~1050 on the left-Y-axis (i.e., 527.8 * 2 = 1055.6).
In that year, there were roughly 1580 T. longicornis, which is ~1050 more than (double) the ClimAvg (~525).
From ~1985 to ~2010, T. longicornis went from roughly 1600 animals per cubic meter to less than 200.
The RIGHT section above shows the Annual Trends (left-most column), Time Window (e.g., "TW10", "TW15"), and Monthly Trends (right 12 columns).
Positive trends are indicated with a "+" symbol while negative trends are indicated with a "-" symbol.
Trends that are statistically significant (p<0.05) are colored red (if positive) or blue (if negative).
Gray +/- symbols indicate a general trend direction, but non-significant.
A gray zero ("0") indicates months with data present but no trend (a near-zero-value slope).
A blank (white area, no symbols) indicates months or years with no or not enough data to qualify for the active time window.
The sub-figure example to the left shows a variable with a seasonal trend pattern.
Here the annual (negative) trends are heavily due to strong negative trends found only in the summer months.
In more recent years (e.g., TW05, TW10, TW15), there have also been additional strong decreasing trends in January/February.
In cases were the trend is flat or has near-zero-slope (see sub-figure example to right), the annual or monthly trends is marked with the text "flat" or a zero ("0") symbol.
This indicates that data were present but had no trend.
Special Cases and Notations:
Sometimes the middle section plot (e.g., show interannual anomalies of a periodically-absent plankton or meroplankton) may have a letter "X" near the anomaly bars zero-line.
An "X" indicates any year where that species or taxa was absent in all sampled months of that year.
In cases where the right-Y-axis "ratio anomaly" value is greater than 5 (e.g., perhaps during a large bloom), the Y-axis maximum value is set to 5 and a star symbol is placed on that year's anomaly bar.
Marking and trimming the Y-axis maximum from very large values allows the trends and patterns of the smaller values to still be visible. If this was not done, a single, very tall anomaly could skew the Y-axis beyond readability.
How to use the Standard Figure-Set Layout Tool click this box to show the standard figure layout tool information section