Contribution of solar radiation to decadal temperature variability over land

Abstract

Global air temperature has become the primary metric for judging global climate change. The variability of global temperature on a decadal timescale is still poorly understood. This paper examines further one suggested hypothesis, that variations in solar radiation reaching the surface (R s ) have caused much of the observed decadal temperature variability. Because R s only heats air during the day, its variability is plausibly related to the variability of diurnal temperature range (daily maximum temperature minus its minimum). We show that the variability of diurnal temperature range is consistent with the variability of R s at timescales from monthly to decadal. This paper uses long comprehensive datasets for diurnal temperature range to establish what has been the contribution of R s to decadal temperature variability. It shows that R s over land globally peaked in the 1930s, substantially decreased from the 1940s to the 1970s, and changed little after that. Reduction of R s caused a reduction of more than 0.2°C in mean temperature during May to October from the 1940s through the 1970s, and a reduction of nearly 0.2°C in mean air temperature during November to April from the 1960s through the 1970s. This cooling accounts in part for the near-constant temperature from the 1930s into the 1970s. Since then, neither the rapid increase in temperature from the 1970s through the 1990s nor the slowdown of warming in the early twenty-first century appear to be significantly related to changes of R s .global dimming | global brightening | global warming | surface incident solar radiation | decadal variability G lobal temperature has become the primary metric for judging global climate change, although many other factors are recognized to be of comparable importance. The overall increase of global temperature over the last century has been largely attributed to the increase of greenhouse gases (1). Less well understood are the reasons for the variability of this increase on a decadal timescale. In particular, warming from 1900 to 1940 was followed by three decades of flat or slightly decreasing temperature, then three decades of very rapid temperature increase, then so far in this century, very little additional increase. The two most plausible explanations for the decadal variability are natural climate variability and variable degrees of cooling from anthropogenic releases of sulfur gas producing sulfate aerosols (2). This effect has long been proposed as a mechanism to counter greenhouse warming (3), has become the basis for many geoengineering proposals (4), and has been used to attribute the lack of warming so far this century to the rapid growth of aerosols in Asia (5).Besides the difference in sign of their temperature effects, sulfate aerosols are distinguished from greenhouse gases in that they only affect daytime radiation, i.e., surface incident solar radiation (R s ). Some kinds of natural variability can also act through affecting R s , i.e., those involving cloud properties.Changes of aerosol loading and ...

500-year climate cycles stacking of recent centennial warming documented in an East Asian pollen record

“…Climate modeling and observation data provide a mechanism that solar forcing triggers the surface temperature variability and atmospheric dynamic 15,[42][43][44] . If TSI reduces (increases), the downward-propagating effects triggered by changes in stratospheric ozone lead to cooling (warming) of stratosphere and global land surface temperature 15,42,43 . Atmospheric responses to reduced solar irradiance could lead to the coincident increases in North Atlantic drift ice, reduces of NADW intensity, cooling of both the ocean surface and high-latitude continent around North Atlantic and North Pacific, and trigger the negative state of Arctic Oscillation/North Atlantic Oscillation (AO/NAO) 6,44,45 .…”

“…Atmospheric responses to reduced solar irradiance could lead to the coincident increases in North Atlantic drift ice, reduces of NADW intensity, cooling of both the ocean surface and high-latitude continent around North Atlantic and North Pacific, and trigger the negative state of Arctic Oscillation/North Atlantic Oscillation (AO/NAO) 6,44,45 . When TSI reduced (increased), northern highlatitude terrestrial region experienced cool (warm) climate 5,6,15,45 . This effect could lead to the increases (decreases) drift ice and weaken (strengthen) the variability of NADW 5,6,45 .…”

“…Observations and model simulations over recent centuries suggested that multidecadal to multicentennial cyclic change of solar activity and climate patterns (such as Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Deep Water) still existed under anthropogenic forcing and played an important role in regulating global to regional terrestrial (EA, North America, and Europe) and marine (North Atlantic and Pacific) climate change during the past centuries [9][10][11][12][13][14][15] . But recent studies based on global and regional climate records indicated that the warming of the past century is unprecedented and not relative to natural forcing but anthropogenic forcing 4,16,17 .…”

The Global Energy Balance Archive (GEBA) version 2017: a database for worldwide measured surface energy fluxes

“…These include for example their implications for evaporation changes (Wang et al, 2010), for changes in the intensity of the global water cycle (Wild, 2012), for global warming and diurnal temperature range Makowski et al, 2009;Wang and Dickinson, 2013a), for changes in isoprene emissions (Stavrakou et al, 2014), and for glacier melt Huss et al, 2009). Further, GEBA data were used for the assessment of the worldwide variation in diffuse and direct shortwave radiation of relevance for biosphere growth, agricultural production, and tree-ring density (Mercado et al, 2009;Wild et al, 2012;Stine and Huybers, 2014).…”

Impact of land use/land cover change on changes in surface solar radiation in eastern China since the reform and opening up

“…Therefore, the DTR is a good proxy of SSR in both temporal and spatial scales and is widely used (e.g. , Wild 2009b;Wang and Dickinson 2013). Compared with direct SSR measurements, the advantage of DTR is that it is measured globally with a network of much higher density and earlier records (Wild 2009a).…”