Ongoing changes in snow cover significantly affect vegetation productivity, but the actual effect of snow cover remains unclear due to a poor understanding of its lagged effect. Here, we used multisource datasets to investigate the lagged effect of snow cover on vegetation productivity in Northern Hemisphere ( > 40°N) ecosystems from 2000 to 2018. We found a widespread lagged effect of snow cover ( > 40%, P < 0.05) on growing season vegetation productivity (mean ~73-day lag). The effect of snow cover on vegetation productivity was underestimated by over 10% of the areas without considering regional lagged time differences. A longer lagged effect generally occurred in warm and humid areas, and areas with increased lagged time (66%) were greater than those with decreased trends. Moreover, changes in lagged effect were strongly driven by climate factors, followed by soil and topography factors. These findings emphasize the need to consider lagged time differences of snow cover when investigating snow-vegetation productivity interactions.

Sea surface salinity (SSS) plays an important role in global water cycle. In recent years, satellite based remote sensing has proven to be a promising approach for global SSS observation. A new payload concept, named MICAP (microwave imager combined active and passive), has been introduced in this paper. MICAP is a suit of active/passive instrument package, which includes L/C/K band one-dimensional MIR (microwave interferometric radiometer) and L-band DBF (digital beamforming) scatterometer, sharing a parabolic cylinder reflector. MICAP has been selected to be a candidate payload for future Chinese ocean salinity mission. In this paper, the MICAP instrument concept, specification and preliminary system design will be introduced.

Ongoing warming intensifies snowpack extremes, posing significant hydroclimatic risks to socio-ecological systems. However, the relation between snowpack extremes and subsequent compound hydroclimatic extremes remains unclear. Here, we investigated the impact of snowpack extremes on warm-season compound hydroclimatic extremes in the Northern Hemisphere using multisource datasets from 1980 to 2022. We found widespread increases in deficient, short, and deficient-short snowpack extremes, triggering more compound hot-dry extremes within a month after snowpack disappearance (mean coincidence rate over 0.6, p < 0.05). The impact of compound snowpack extremes exceeded that of individual snowpack extremes in both areas (over 10%) and coincidence rates (over 0.2). Meanwhile, increased intensity, rather than frequency, of snowpack extremes drove mainly the occurrence of compound hydroclimatic extremes. Furthermore, background climate factors, followed by vegetation, topography, and soil, affected relations between snowpack and compound hydroclimatic extremes. These findings will deepen our understanding of the emerging consecutive extremes and improve their predictability.

Temporary ice roads built by the process of snow compaction, watering, and icing during cold winters are lifelines for land access in remote Arctic. In the context of the Arctic amplified warming, the vulnerability of potential ice roads under the influence of complex climate system remains unclear. Here, we construct a potential ice road assessment model that allows quantization of the climatic suitability of potential ice roads in the Arctic. Using satellite remote sensing and meteorological data, we find changes in surface air temperature and snow cover reduced the climatic suitability of potential ice roads during 1979–2017. Spatially, potential ice roads in North America face more immediate threats due to decreased snow depth compared to Eurasia. Before the end of the 21st century, we project a further decline in the climatic suitability of potential ice roads, primarily due to increasing surface air temperatures and decreasing permafrost stability. Taking precious metal/diamond exploration as an example, we conclude that mining activities associated with ice roads will face access difficulties by 2050–2100 due to the decreased potential ice roads. These results give new insights into the challenges and opportunities of Arctic overland travel.