Greenland 2022-23 SMB, melting and GRACE mass

[John_the_Younger]

As goes Greenland, so goes the Arctic?
(Greenland had record mass losses in 2012 and the (current) minimum Arctic sea ice area happened that year.)
[Investing advice: past experience does not guarantee future returns.]

[gerontocrat]

Wow.

Daily melt 8th July wower.

[interstitial]

That is the highest I recall ever seeing it. Is it a record?

[HapHazard]

I'm hoping to hike the Arctic Circle Trail in Greenland sometime in the next 5 or so years. I'm starting to think I should speed things up if I want to see any ice...

[sidd]

Re: is it a record

it all melted about a decade ago

sidd

[gerontocrat]

It certainly did - in 2012. The cumulative melt and the SMB (Surface Mass Balance) losses during the melt season were so high that no year since has been anywhere close. An extreme extreme outlier.

DMI have the data, but have not published the daily Melt and SMB data for the years before 2017. They have plans to do so, but no funding. Budget on a shoestring syndrome.

NSIDC Greenland Today publish a dataset of daily melt going back to 1979, but not for SMB, which in the end is the more important metric for the GIS mass balance trend. However they must use a different model from DMI for melt, as the results differ from day to day and overall produce daily melt data somewhat lower than that from DMI.

Here are 2 graphs I made from that data that show how extraordinary 2012 was.

Last EDIT: Despite that extraordinary melt, over the DMI year Sept to Aug precipitation exceeded melt+runoff, so the SMB increased but by much less than average. The trend is for melt to increase but also precipitation, so annual SMB increase is expected to increase further until a tipping point is reached, caused by higher melt and more precipitation falling as rain on snow events. Someone needs to cough up funding so DMI can do more including more published data.

[interstitial]

While ultimately volume changes over time or SMB are more important I was wondering about the extent percentage. Did the extent percentage for one day melt exceed its current level? Was saying it all melted indicating it reached 100% at some point?

[kassy]

The peak is nearly double which is about the area which is white in the last picture of this year.

[gerontocrat]

While ultimately volume changes over time or SMB are more important I was wondering about the extent percentage. Did the extent percentage for one day melt exceed its current level? Was saying it all melted indicating it reached 100% at some point?

The area of Greenland is 2,166,086 km2
The area of the GIS (Wikipedia) is 1,755,637 km2
The area of the GIS (NSIDC) is 1.71 million km2

The maximum daily melt in 2012 per NSIDC's "Greenland Today" was on July 11 at 1,463,750 km2, 85.6% of the GIS area using the NSIDC measurement.

Although 3 days in 2012 were higher than the current values of 2023 daily melt from DMI, the extreme spike in 2012 only lasted about 7 days, while the current 2023 extreme values have lasted 12 days so far.

So maybe 2023 is setting some sort of record for the length of time of sustained extreme melt.

Caveat: I believe Greenland Today uses a somewhat different algorithm to measure daily melt from that used by DMI. The Greenland Today values of recent years seem to be consistently lower than those of DMI. So maybe the comparison is invalid? Mixing different measurement systems of the same data seems always to bring problems.

[interstitial]

Thanks Gerontocrat for the explanation. Interesting stuff.

[oren]

The extreme melt year of 2012 had two separate intense melt events. The mostunusual melt event occurred on 11–12 July 2012 and was unprecedented during this and the previouscentury, covering ~99% of the ice sheet surface including areas >3000 m at Summit Station (Figure 1a)according to data from multiple satellite sensors [Nghiem et al., 2012]. Melt this extensive had not occurredsince 1889 (+/1 year) according to ice core records [Nghiem et al., 2012; Clausen et al., 1988; Alley andAnandakrishnan, 1995]. Another large melt event occurred on 29 July 2012, where ~79% of the surfaceexperienced some melt according to data from multiple satellite sensors [Nghiem et al., 2012].

https://www.researchgate.net/publication/260335067_Greenland_Ice_Sheet_Melt_from_MODIS_and_Associated_Atmospheric_Variability#pf2

[sidd]

There was also an atmospheric river involved in 2012. I haven't the time to find the paper, but i believe i put a link to it somewhere i n this forum.

sidd

[gerontocrat]

The extreme melt year of 2012 had two separate intense melt events. The mostunusual melt event occurred on 11–12 July 2012 and was unprecedented during this and the previouscentury, covering ~99% of the ice sheet surface including areas >3000 m at Summit Station (Figure 1a)according to data from multiple satellite sensors [Nghiem et al., 2012]. Melt this extensive had not occurredsince 1889 (+/1 year) according to ice core records [Nghiem et al., 2012; Clausen et al., 1988; Alley andAnandakrishnan, 1995]. Another large melt event occurred on 29 July 2012, where ~79% of the surfaceexperienced some melt according to data from multiple satellite sensors [Nghiem et al., 2012].

https://www.researchgate.net/publication/260335067_Greenland_Ice_Sheet_Melt_from_MODIS_and_Associated_Atmospheric_Variability#pf2

The Greenland Today data says that the July 11 2012 melt was 85.6% of the area of the Greenland ice sheet. Different algorithms, different results.

[gerontocrat]

Meanwhile in 2023......

DMI data as at 10th July

Daily melt once again above 65%. It seems to me that once again the concentration of attention on one day records takes attention away from what may be a lower value but sustained over an unusually long period. In 2023 the effect can be seen on the accumulated melt line on the graph.

SMB loss on this day well above average.

It looks like high daily melt and relatively low precipitation will be maintained for the next few days. But by day 7, the Greenland High basically disappears, and melt may return to average or below average levels. The absence of a blocking high may also allow increased precipitation mostly from the South and SouthWest, which being warm may include significant rain on snow reaching to higher altitudes, that could keep SMB losses high.

[gerontocrat]

July 12 - and it continues....

[interstitial]

14 days in a row over 55 % and 4 of the last 5 days over 65%. That is not good.

[Alexander555]

How would the accumulated anomaly since sep 1 look like ?

[gerontocrat]

How would the accumulated anomaly since sep 1 look like ?

The current accumulated melt in 100% days equivalent on July 11 2023 is 14.31. The corresponding data for 2022 is 10.06, and for the 2017-2022 average is 12.00. I cannot give you a figure for the long-term average as the DMI data is not available to me.

[Alexander555]

That positive anomaly on the edge of the west side is probably gone in the last 10 days. That includes the area that's connected with the future "  lake greenland ". How would that area ( where the water meets the ice)  look like today ? Is it like a bay, or like a river ?

[gerontocrat]

Attached is the Greenland bedrock map, i.e. with the ice sheet removed. The future in n thousand years from now where n is the unknown quantity.

Also attached is the current accumulated SMB anomaly map.

[gerontocrat]

DMI data as at 12th July

Daily melt above 60% for WHOOPS 8 7 days in a row, and above 50% for 16 days in a row.
The effect can be seen on the accumulated melt line on the graph which has left the 2017-2022 average well behind.

This length of time of sustained melt must be in record territory.

SMB loss on this day well above average. However, accumulated SMB gain this year is still well above the longterm average, though it has dipped below the 2022 accumulated SMB.
On this day, at 552GT accumulated SMB is now 46GT (9%) above the 2017-2022 average of 506GT.

The Greenland High weakens and centres over NE Greenland. Daily melt may remain at higher than average levels. The absence of a blocking high may also allow increased precipitation mostly from the South and SouthWest, which being warm may include significant rain on snow reaching to higher altitudes, that could keep SMB losses high.

When I have time (bad joke?) I will post some gifs on SMB and melt.

[oren]

Daily melt above 60% for 8 days in a row, and above 50% for 16 days in a row.

Amazing.

[interstitial]

Daily melt above 60% for 8 days in a row, and above 50% for 16 days in a row.

Amazing.

A day later and I count 7 days above 60% and 16 days above 50%. It is hard for me to count the lines apparently.

[gerontocrat]

Daily melt above 60% for 8 days in a row, and above 50% for 16 days in a row.

Amazing.

A day later and I count 7 days above 60% and 16 days above 50%. It is hard for me to count the lines apparently.

Ok, my bad

& here are gifs for Accumulated and Daily SMB since the maximum SMB on 27th June, and daily melt from the same day.

The Accumulated SMB map shows SMB increasing in the West, reflecting that most precipitation is coming from the SouthWest. AS yet all the daily melt has yet to make a big impact on SMB - much melt being absorbed into the ice and compacted snow cover?

click gifs to start, each runs 6 times.

[interstitial]

Daily melt above 60% for 8 days in a row, and above 50% for 16 days in a row.

Amazing.

A day later and I count 7 days above 60% and 16 days above 50%. It is hard for me to count the lines apparently.

Ok, my bad

I think it was my error I looked at previous day again and came up with the corrected numbers.

[gerontocrat]

DMI data as at 13th July

Daily melt above 60% for 8 days in a row, and above 50% for 17 days in a row.
The effect can be seen on the accumulated melt line on the graph which has left the 2017-2022 average well behind.

This length of time of sustained melt must be in record territory.

SMB loss on this day well above average. However, accumulated SMB gain this year is still well above the longterm average, though it has dipped below the 2022 accumulated SMB.
On this day, at 543GT accumulated SMB is now 40GT (8%) above the 2017-2022 average of 503GT.

GFS forecasts that the Greenland High weakens and basically disappears by day 7. Daily melt may be highly variable in the next week or so - both quite low and very high. The absence of a blocking high may also allow increased precipitation mostly from the South and SouthWest, which being warm is forecast to include significant rain on snow reaching to higher altitudes, that could keep SMB losses high.

[gerontocrat]

Data as at 14 July

Images attached (daily melt only 59.97%)

[gerontocrat]

DMI data as at 15th July

Daily melt was above 60% for 8 days in a row, and is above 50% for 19 days in a row.
The accumulated melt line on the graph has left the 2017-2022 average well behind curretly on course to be a record for the years from 2017.

This length of time of sustained melt must also be in record territory.

SMB loss on this day well above average. However, accumulated SMB gain this year is still well above the longterm average, though it has dipped below the 2022 accumulated SMB.
On this day, at 529GT accumulated SMB is now 35GT (8%) above the 2017-2022 average of 494GT.

The high melt but also high SMB is in line with most model projections. They project that as the years go by melt will increase but so will SMB as warmer wetter air brings more precipitation. If AGW persists a tipping point will be reached as a warmer Greenland means SMB includes more rain on snow events even in winter, which increases run-off and by reducing albedo allows insolation to increase melt in summer.

GFS forecasts that the Greenland High weakens and moves to the NE and basically disappears by day 7. Daily melt may be highly variable in the next week or so - both quite low and very high with very high melt possible in days 4 to 6 and reduced melt in days 7 to 10. The absence of a blocking high may also looks like allowing increased precipitation mostly from the South and SouthWest, which being warm is forecast to include at least one significant rain on snow in 4 days time in the West reaching to higher altitudes, that could keep SMB losses high.

[gerontocrat]

DMI data as at 16th July

Daily melt was above 60% for 8 days in a row, and is above 50% for 20 days in a row.
The accumulated melt line on the graph has left the 2017-2022 average well behind, and is  currently on course to be a record for the years from 2017.

This length of time of sustained melt at this level must also be in record territory.

SMB loss on this day above average. However, accumulated SMB gain this year is still well above the longterm average, though it has dipped below the 2022 accumulated SMB.
On this day, at 524GT accumulated SMB is now 34GT (7%) above the 2017-2022 average of 490GT.

The high melt but also high SMB is in line with most model projections. They project that as the years go by melt will increase but so will SMB as warmer wetter air brings more precipitation. If AGW persists a tipping point will be reached as a warmer Greenland means SMB includes more rain on snow events even in winter, which increases run-off and by reducing albedo allows insolation to increase melt in summer.

GFS still forecasts that the Greenland High weakens and moves to the NE and basically disappears before day 7. Daily melt may be highly variable in the next week or so - both quite low and very high with very high melt possible to days 4 to 6 and then reduced melt in days 7 to 10. The absence of a blocking high may also looks like allowing increased precipitation mostly from the South and SouthWest, which being warm is forecast to include at least one significant rain on snow event in the SouthWest reaching to higher altitudes, that could keep SMB losses high.

[gerontocrat]

Images only today. The melt goes on.

[gerontocrat]

DMI data as at 18th July

Daily melt was above 60% for 8 days in a row, is up above 60% (just) on this day, and is above 50% for 22 days in a row.

The accumulated melt line on the graph has left the 2017-2022 average well behind, and is  currently on course to be a record for the years from 2017.

This length of time of sustained melt at this level must also be in record territory.

SMB loss on this day above average. However, accumulated SMB gain this year is still well above the longterm average, though it has dipped below the 2022 accumulated SMB.
On this day, at 512GT accumulated SMB is now 32GT (7%) above the 2017-2022 average of 481GT.

The high melt but also high SMB is in line with most model projections. They project that as the years go by melt will increase but so will SMB as warmer wetter air brings more precipitation. If AGW persists a tipping point will be reached as a warmer Greenland means SMB includes more rain on snow events even in winter, which increases run-off and by reducing albedo allows insolation to increase melt in summer.

GFS still forecasts that the Greenland High weakens and moves to the NE and strengthens by day 7 and beyond. Daily melt may be highly variable in the next week or so - both quite low and very high with very high melt possible to days 4 to 6 and then significantly reduced melt after day 4.

The absence of a strong blocking high may also looks like initially allowing increased precipitation mostly from the South and SouthWest, which being warm is forecast to include at least one significant rain on snow event in the SouthWest reaching to higher altitudes, that could keep SMB losses high. By day 7 as the high strengthens, lows are forced westwards south of Greenalnd leaving Greenland mostly dry - and sunny?

Overall it looks more likely that this period of extreme melt will return to more normal levels within the next week

[gerontocrat]

As at 19th July images only today.

[gerontocrat]

There are two sources of data for Greenland Surface Melt, DMI and NSIDC's Greenland Today.

This post is to explain why I feel unable to use the data from NSIDC's Greenland Today even though it is a full dataset of daily data going back to 1979 while DMI's daily dataset only goes back to 2017.

Greenland Today issues surface melt data by Km2. DMI issues surface melt data by percentage of the Greenland Ice Sheet melting. In the graphs attached I converted to DMI's Percentage data to Km2 area by using NSIDC's Greenland Ice Sheet measure of 1.71 million km2.

The first graph shows the difference between DMI and Greenland Today of daily melt in 2023 and the 2017-2022 average. The Greenland Today data is significantly less than the DMI data.

The 2nd graph shows the impact on the cumulative melt data. For the 2017-2022 average, by the end of the melting season the Greenland Today data is less than half that of the DMI data. A similar outcome is shown for 2023 data to date.

It is normal to have different results of the same event from different sources using different algorithms. But this difference is extreme. I have checked my calculations, and unless I have had a brain breakdown the analysis is sound.

If anyone has any info on this please post it, as I will be sending emails to DMI and NSIDC asking for their comments.

[gerontocrat]

DMI data as at 20th July

Daily melt was above 60% for 8 days in a row, below 60% (just) on this day, and is above 50% for 24 days in a row.

The accumulated melt line on the graph has left the 2017-2022 average well behind, and is  currently on course to be a record for the years from 2017.

This length of time of sustained melt at this level must also be in record territory.

SMB loss on this day above average. However, accumulated SMB gain this year is still well above the longterm average, though it has dipped below the 2022 accumulated SMB.
On this day, at 500GT accumulated SMB is 28GT (6%) above the 2017-2022 average of 472GT.

GFS now forecasts that a moderate Greenland High strengthens a bit. Daily melt may be highly variable in the next week or so - but in general reducing somewhat over the forecast period.

The absence of a strong blocking high may also looks like allowing some precipitation mostly from the South and SouthWest, which being warm is forecast to include occasioanl rain on snow events in the SouthWest reaching to higher altitudes, that could keep SMB losses above average. As the high strengthens, Greenland gets drier - and sunnier?

Overall it looks more likely that this period of extreme melt will return to more normal levels within the next week

[gerontocrat]

Images only today...

[gerontocrat]

NASA / JPL have issued Greenland Mass Balance data for another month to mid-May 2023.

A small gain in Greenland Mass in the month due to SMB gains being greater than GIS mass loss from glaciers calving and melting by ocean waters.

[gerontocrat]

DMI data as at 22nd July

Daily melt was above 60% for 8 days in a row, below 60% (just) on this day, and is above 50% for 26 days in a row.

The accumulated melt line on the graph has left the 2017-2022 average well behind, and is  currently on course to be a record for the years from 2017.

This extremely lengthy sustained melt at this level must also be in record territory.

SMB loss on this day above average. However, accumulated SMB gain this year is still well above the longterm average, though it has dipped well below the 2022 accumulated SMB.
On this day, at 489GT accumulated SMB is 26GT (6%) above the 2017-2022 average of 463GT.

GFS now forecasts that the weak Greenland High strengthens somewhat over the next week or so. Daily melt looks to generally reduce somewhat over the forecast period, with the high increasingly blocking precipitation especially after days 1 to 3. Perhaps a drier and sunnier Greenland in prospect?

Overall it looks more likely that this period of extreme melt will return to more normal levels but maybe at or above average within the next week while daily SMB losses stay above average

[gerontocrat]

DMI data as at 23rd July

Only images today, but the melt goes on

[gerontocrat]

Updated graphs comparing Greenland Today melt data with DMI melt data are attached (1st & 2nd images).

The Greenland Today melt data is concistently less than the DMI data. Nevertheless the Greenland Today graphs (3rd & 4th images) show that without the very slow 2023 melt from April to late June 2023 melt to date might have been close to the 2012 extreme record.

[gerontocrat]

DMI data as at 22nd July

Daily melt was above 60% for 8 days in a row, below 60% (just) on this day, and is above 50% for 28 days in a row.

The accumulated melt line on the graph has left the 2017-2022 average well behind, and is  currently on course to be a record for the years from 2017.

This extremely lengthy sustained melt at this level must also be in record territory.

SMB loss on this day above average. However, accumulated SMB gain this year is still somewhat above the longterm average, though it has dipped well below the 2022 accumulated SMB. On this day, at 476GT accumulated SMB is 21GT (5%) above the 2017-2022 average of 455GT.

GFS now forecasts that the Greenland High persists but variable in strength and location during the next week or so. Daily melt looks to generally reduce somewhat over the forecast period, with the high keeping Greenland mostly dry and sunny.

Overall it looks more likely that this period of extreme melt will return to more normal levels but maybe at or above average within the next week while daily SMB losses may stay above average

[OffTheGrid]

How often do they do full gravity scans. How much of this is modeled? How often is there altimetry data?

[gerontocrat]

How often do they do full gravity scans. How much of this is modeled? How often is there altimetry data?

Je ne sais pas. But DMI funding is totally inadequate for both the scale and importance of the task they face.

Meanwhile,

DMI info as at 25th July

Daily melt at 47% is below 50% for the first time since June 26th.

Daily SMB loss is well above average again, with accumulated SMB gain at 470 GT now 19GT above the 2017-2022 average of 451GT.

[gerontocrat]

DMI info as at 26th July

Daily melt at 44% is still well above avereage.

Daily SMB loss is well above average again, with accumulated SMB gain at 463 GT now 15GT (3%) above the 2017-2022 average of 448GT.

The GFS forecast has the Greenalnd High strengthening over the next week to 10 days, with Greenalnd becoming cooler and staying mostly dry. SMB daily losses may stay well above average while daily melt initially declines and perhaps increases a bit after day 7.

[gerontocrat]

DMI info as at 27th July

Daily melt at 42% is still well above avereage.

Daily SMB loss is well above average again, with accumulated SMB gain at 457 GT now 13GT (3%) above the 2017-2022 average of 444GT.

[gerontocrat]

DMI info as at 29th July

Daily melt at 41% is still well above avereage.

Daily SMB loss is just below average on this day, with accumulated SMB gain at 448 GT now 13GT (3%) above the 2017-2022 average of 435GT.

The Greenland High still looks like it will strengthen though temperatures suggest daily melt may reduce to more average levels and precipitation looks like remaining subdued.

[gerontocrat]

DMI info as at 30th July

Daily melt at 38% is lower but still well above avereage.

Daily SMB loss is just below average on this day, with accumulated SMB gain at 445 GT now 16GT (4%) above the 2017-2022 average of 429GT.

The Greenland High still looks like it will strengthen though temperatures suggest daily melt may stay reduced to more average levels and precipitation looks like remaining lowish.

[gerontocrat]

DMI data as at 31 July

Daily melt at 36% is lower but still well above avereage.

Daily SMB loss of 2.0 GT is well below the average on this day of 5.8GT, with accumulated SMB gain at 443 GT now 20 GT (5%) above the 2017-2022 average of 423GT.

The Greenland High still looks like it will strengthen though temperatures suggest daily melt may  reduce some more to more average levels, though it may pick up after a week. Precipitation looks like average to lowish.

[Niall Dollard]

Gif showing the recent snow accumulation over northern Greenland. Needs a click

[gerontocrat]

DMI data as at 2nd August

Daily melt at 33% is lower but still above avereage for the time of year

Daily SMB loss of 0.5 GT is well below the 2017-2022 average on this day of 4.9 GT, with accumulated SMB gain at 442 GT now 29 GT (7%) above the 2017-2022 average of 413GT.

The Greenland High still looks like it stay though temperatures suggest daily melt may reduce some more to more average levels, though it may pick up after a week. Precipitation looks like average to lowish to maybe higher with orecipitation from the Wast in days 7 to 10.

[gerontocrat]

Only time for the images today - i.e. no blurb