We’re going back to the same basic imagery today with some new commentary, covering certain points that need extra discussion and highlighting. There is a big event of considerable importance going on these days, from the standpoint of climate science, and that is the constant warming of air temperatures over the Arctic Ocean, day after day with no breaks. While everything else in this overall part of the hemisphere keeps changing on most days, the singular warming trend we’ve been watching remains stubbornly constant. That’s worrisome, if only by reason for what it means in terms of adding small increments of heat to the entire iced-over surface of the ocean. These additions should help to speed up the rate of ice loss from surface melting all summer long, and total extent as well. Adding to the problem, a new study has just been published by a team of oceanographers who show “how plumes of warm water are flowing into the Arctic Ocean from the Pacific Ocean and accelerating sea ice melt from below.” You can read all about it, including access to the full study, in a press release from Bangor University at this link: https://phys.org/news/2021-04-arctic-sea-ice.html. I think the research work done by this group adds a convincing element to a picture of already overwhelming complexity and magnitude. Now for today’s anomaly map:
The first thing to note is that, except for the Barents Sea to the east of Svalbard, just a little less than 100% of the ocean itself and the seas that surround it are covered by an unbroken warm anomaly, one showing an average upward temperature adjustment of not less than 6C for a full 24 hours a day. Before long this kind of warmth is sure to leave a mark on the surface below, and a surface made of ice, but not yet ready to melt, is no exception. The thing I want you to focus on today is not the ocean’s anomaly but the size and comparable warmth of the anomalous region extending southward, all the way down to the latitude of southern Mexico. This anomaly, like almost all other warm daily anomalies, will prove to be associated with above average readings of atmospheric content of precipitable water (PW) for the day in every part of its location. We know the actual current PW readings but we don’t know for sure the exact historical averages. We can make good estimates, and we know for sure that these averages will vary a great deal from place to place. Greenland, as an outstanding example, is bound to have much lower current and average readings than any surrounding surface, and would thus require only a relatively small amount of extra PW content in order to rise above its average. Keep the principle behind this relationship in mind everywhere when you see the next map, because variations abound:
Whatever is viewed on the above two maps is all current, composed from the average of a single day of multiple readings. The PW you see in every warm location can be thought of as the major factor causing the warm anomaly reported for that location. Now consider the strong likelihood that a large percentage of those PW molecules are located in the upper part of the troposphere, that all of the molecules in that upper location are constantly moving, and that the preferred direction of movement is first of all northward, toward the pole, and secondarily eastward. The secondary direction is the result of movement preferred by most of the winds at that level, which have a well-defined capacity for transporting or otherwise influencing the movement of all PW molecules. As mentioned, every molecule on the PW map is first of all aiming for the polar zone as it moves. Some are just one day away, some two days, and so on, up to perhaps five or six days. They all have short lives to begin with, and most keep dropping out during transport in some form of precipitation.
There is one more consideration to keep in mind, resulting from the tendency for all PW molecules in the upper atmosphere to drift eastward as well as poleward. I suspect that this movement is more pronounced in the mid-latitudes than high latitudes, with application to both the entire streams of PW concentration and to positioning of the daily anomalies they produce. Close examination aimed at noting any such eastward movement over any consecutive series of days lends support to the idea. We can still feel quite confident that the bulk of all concentrated PW within a day or two of reaching the pole as it heads northward is likely to come very close to succeeding. What this means, when looking at the above pair of maps, and the very wide swath of anomaly warmth in the one stream we are focused on, makes it seem inevitable that more of the same kind of warming that is now affecting the ocean will continue for at least a few more days. Streams approaching from other directions are also in sight, and are subject to the same type of reckoning.
Carl