In pictures taken from the International Space Station, most of North Korea is shrouded in darkness - but it's the tiny specs of light that are worth examining, says Witness to Transformation

New images taken by an astronaut on the International Space Station this year captured a fresh view of the Korean peninsula at night.

Though the theme is familiar – "light emission from Pyongyang is equivalent to the smaller towns in South Korea” – this picture has in fact been changing.

Other cities and even smaller towns are now visible, and therein lies a new way of tracking economic activity in North Korea that has been used elsewhere with interesting effect (see for example Small, Pozzi and Elvidge and Henderson and Weil).

In this analysis, we use the DMSP-OLS Stable Lights Dataset covering 1992-2012 to measure changes in luminosity in North Korea over time. In effect, this data set generates a single composite image of the country for each year, and can be used as a proxy for economic activity across different parts of North Korea. The basic units of observation are the 186 local administrative areas defined by the Global Administrative Areas dataset.

North Korea by night - the single composite image of the country for 2012.

Image and data processing by NOAA's National Geophysical Data Center. DMSP data collected by US Air Force Weather Agency. (DMSP-OLS Stable Lights Image 2012) Photograph: Piie

The images remove background noise and ephemeral lights emitted from gas flares or fires, but there is one major drawback: the six satellite sensors are not sufficiently inter-calibrated to make direct year-to-year comparisons. What it is possible to do, however is to compare the shares of total light emanating from different jurisdictions (again, from local administrative areas up to regions). Put differently, we can’t say what the absolute growth of luminosity is in Pyongyang. But we can track changes in Pyongyang’s share of all light emanating from the country. As a result, the data is quite useful for showing changes in the spatial distribution of economic activity.

To look at larger regional aggregations, we divide the country into five regions:

Pyongyang;

The north-west, consisting of North Pyongan province, South Pyongan province, Chagang province, and the city of Sinuiju;

The north-east, including the Hamgyeong provinces, Ryongyang province, and the Rason special city;

The south-east including Gangweon province and the Kumgangsan special administrative area;

The south-west, including North Hwanghae province, South Hwanghae province, and the city of Kaesong.

The figure below shows the three-year moving average of each region’s share of total national light from 1996 to 2011. The graph on the right omits Pyongyang, allowing us to see more clearly what is going on in the provinces.

Share of total national light from 1996 to 2011 emitted by regions of North Korea. Photograph: Piie

Three important trends are visible. First, Pyongyang’s share declined from its 1996-97 peak — in the immediate aftermath of the famine–until the early-2000s. A possible interpretation: Pyongyang had been protected during the famine, but once it ended other areas began to recover. From 2003, however, the capital city’s share rebounded to mid-90s levels before turning down slightly in 2011.



Second, the biggest gainer in the immediate aftermath of the famine was the Northwest. The decline in Pyongyang’s relative share was matched almost exactly by strong relative growth in the north-west region. The entirety of the Pyongyang-Sinuiju corridor, which connects the capital with China’s northeastern provinces, falls within this region. This uptick in luminosity corresponds with an inflection in China-DPRK trade that we have documented in earlier posts (see here, here, and here for some recent examples). If major infrastructure investments in this corridor continue, such as an express railway from Kaesong to Sinuiju, this momentum of this growth corridor could continue.

Third, the biggest relative loser in this story —particularly apparent when we omit Pyongyang— is the north-east region. Not only was the region hit hardest by the famine but it has fared less well than the other regions since that time too. It is possible that this relative decline is overstated by the difficulty of capturing developments along the borders because of the technical problem of “blooming” across boundaries. Nonetheless, the division between the west and east coasts of the country is apparent.

Finally, although it is too early to call it a trend, it is interesting that Pyongyang’s share drops slightly in 2011 and that all other areas see increases, the south-east more gradually, the north-east and north-west more sharply. A possible interpretation is that the economy has rebounded at least somewhat during the last three years.

Travis Pope contributed to this report