A new wave of portable biosensors allows frequent measurement of health-related physiology. We investigated the use of these devices to monitor human physiological changes during various activities ...and their role in managing health and diagnosing and analyzing disease. By recording over 250,000 daily measurements for up to 43 individuals, we found personalized circadian differences in physiological parameters, replicating previous physiological findings. Interestingly, we found striking changes in particular environments, such as airline flights (decreased peripheral capillary oxygen saturation SpO2 and increased radiation exposure). These events are associated with physiological macro-phenotypes such as fatigue, providing a strong association between reduced pressure/oxygen and fatigue on high-altitude flights. Importantly, we combined biosensor information with frequent medical measurements and made two important observations: First, wearable devices were useful in identification of early signs of Lyme disease and inflammatory responses; we used this information to develop a personalized, activity-based normalization framework to identify abnormal physiological signals from longitudinal data for facile disease detection. Second, wearables distinguish physiological differences between insulin-sensitive and -resistant individuals. Overall, these results indicate that portable biosensors provide useful information for monitoring personal activities and physiology and are likely to play an important role in managing health and enabling affordable health care access to groups traditionally limited by socioeconomic class or remote geography.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Relative humidity (RH) is projected to increase over ocean but decrease over land under anthropogenic warming. The land RH decrease was previously attributed to ocean influences on land changes. ...Here, we show that interactive soil moisture (SM) is necessary and may be sufficient for anthropogenic warming to reduce the land RH. The land RH decrease is absent in simulations with realistic land‐ocean geometry but fixed SM, and present in simulations with interactive SM but no oceans or changes in precipitation minus evaporation. The land RH decrease is coupled to the SM decline and the latter could be understood as a natural response of interactive SM to anthropogenic warming. Specifically, prior to adjustments in SM and RH, evaporation would increase by ∼6% K−1 following the Clausius–Clapeyron relation, outpacing the radiatively constrained ∼2% K−1 precipitation increase. This prior imbalance depletes SM and consequently reduces RH through the coupling between SM and RH.
Plain Language Summary
As a measure of air wetness, relative humidity (RH) is projected to decrease over land under anthropogenic warming, contributing to increasing evaporative demand and intensifying droughts, heatwaves and wildfires. The land RH decrease was previously attributed to influences from ocean, but here we propose an alternative explanation. We first show that the land RH decrease is coupled with the soil moisture (SM) decline. Then, by excluding interactive SM and ocean influences respectively in warming simulations, we illustrate that interactive soil moisture (i.e., soil moisture is fed by precipitation minus evaporation and can in turn affect evaporation through moisture availability) is necessary and may be sufficient to produce a drier land under anthropogenic warming. A conceptual understanding of this declined SM and RH is provided based on theoretical evaporation equations.
Key Points
We propose a new explanation for the projected decrease in land relative humidity under anthropogenic warming
Complex and idealized simulations show that interactive soil moisture (SM) is necessary and sufficient for anthropogenic warming to dry the land
Interactive SM allows prior imbalance in evaporation and precipitation increases to dry the land independent of ocean influence
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
While a large latitudinal displacement of the westerly jet brings about disproportionate socioeconomic impacts over Northern Hemisphere midlatitude continents, it is not well understood as to whether ...the winter circulation will become wavier or less in response to climate change. Here, using observations and large ensembles of climate models, we show that changes in atmospheric waviness can be estimated from the optimal structures of the westerly jet for wavier circulation, which are obtained from an advection‐diffusion model. Thus, the changes in westerly jet structure in climate models under climate change provide a physical constraint on changes in atmospheric waviness, indicating that the North Atlantic wave activity will experience a robust decline in a warmer climate, while future North Pacific wave activity is obscured by model uncertainty rather than internal variability. These findings highlight the changes to jet stream structure as a constraint for regional circulation waviness in a changing climate.
Plain Language Summary
A large latitudinal meandering of Northern Hemisphere winter circulation can induce stagnant weather that causes severe impacts on densely populated East Asia, Western North America, or Western Europe, yet whether the winter circulation will become wavier or less under climate change remains uncertain. Here we analyze observations and large ensembles of climate models and show that changes to atmospheric wave activity under climate change are largely constrained by changes to zonal advecting wind for the Lagrangian motion of air parcels in an advection‐diffusion model. This constraint further indicates a consistent decline in future waviness over the North Atlantic, while changes to future wave activity over the North Pacific are uncertain, due to model uncertainty rather than internal variability of the climate system.
Key Points
Changes in atmospheric waviness can be roughly estimated by changes in zonal advecting wind in an advection‐diffusion model
Changes in the optimal structure of jet stream help constrain regional circulation waviness in a changing climate
Model results suggest future waviness will robustly decline in North Atlantic but is less clear in North Pacific due to model uncertainty
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Studies have indicated that North Pacific sea surface temperature (SST) variability can significantly modulate El Niño–Southern Oscillation (ENSO), but there has been little effort to put ...extratropical–tropical interactions into the context of historical events. To quantify the role of the North Pacific in pacing the timing and magnitude of observed ENSO, we use a fully coupled climate model to produce an ensemble of North Pacific Ocean–Global Atmosphere (nPOGA) SST pacemaker simulations. In nPOGA, SST anomalies are restored back to observations in the North Pacific (>15°N) but are free to evolve throughout the rest of the globe. We find that the North Pacific SST has significantly influenced observed ENSO variability, accounting for approximately 15% of the total variance in boreal fall and winter. The connection between the North and tropical Pacific arises from two physical pathways: 1) a wind–evaporation–SST (WES) propagating mechanism, and 2) a Gill-like atmospheric response associated with anomalous deep convection in boreal summer and fall, which we refer to as the summer deep convection (SDC) response. The SDC response accounts for 25% of the observed zonal wind variability around the equatorial date line. On an event-by-event basis, nPOGA most closely reproduces the 2014/15 and the 2015/16 El Niños. In particular, we show that the 2015 Pacific meridional mode event increased wind forcing along the equator by 20%, potentially contributing to the extreme nature of the 2015/16 El Niño. Our results illustrate the significant role of extratropical noise in pacing the initiation and magnitude of ENSO events and may improve the predictability of ENSO on seasonal time scales.
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BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Identifying bacterial strains in metagenome and microbiome samples using computational analyses of short-read sequences remains a difficult problem. Here, we present an analysis of a human gut ...microbiome using TruSeq synthetic long reads combined with computational tools for metagenomic long-read assembly, variant calling and haplotyping (Nanoscope and Lens). Our analysis identifies 178 bacterial species, of which 51 were not found using shotgun reads alone. We recover bacterial contigs that comprise multiple operons, including 22 contigs of >1 Mbp. Furthermore, we observe extensive intraspecies variation within microbial strains in the form of haplotypes that span up to hundreds of Kbp. Incorporation of synthetic long-read sequencing technology with standard short-read approaches enables more precise and comprehensive analyses of metagenomic samples.
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IJS, NUK, SBMB, UL, UM, UPUK
The fractional increase in global mean precipitation (Formula: see text) is a first-order measure of the hydrological cycle intensification under anthropogenic warming. However, Formula: see text ...varies by a factor of more than three among model projections, hindering credible assessments of the associated climate impacts. The uncertainty in Formula: see text stems from uncertainty in both hydrological sensitivity (global mean precipitation increase per unit warming) and climate sensitivity (global mean temperature increase per forcing). Here, by investigating hydrological and climate sensitivities in a unified surface-energy-balance perspective, we find that both sensitivities are significantly correlated with surface shortwave cloud feedback, which is further linked to the climatological pattern of cloud shortwave effect. The observed pattern of cloud effect thus constrains both sensitivities and consequently constrains Formula: see text. The 5%-95% uncertainty range of Formula: see text from 1979-2005 to 2080-2100 under the high-emission (moderate-emission) scenario is constrained from 6.34Formula: see text3.53% (4.19Formula: see text2.28%) in the raw ensemble-model projection to 7.03Formula: see text2.59% (4.63Formula: see text1.71%). The constraint thus suggests a higher most-likely Formula: see text and reduces the uncertainty by ~25%, providing valuable information for impact assessments.
Abstract Arctic Amplification (AA), the amplified surface warming in the Arctic relative to the globe, is a salient feature of climate change. While the basic physical picture of AA has been ...depicted, how its degree is determined has not been clearly understood. Here, by deciphering atmospheric heat transport (AHT), we build a two-box energy-balance model of AA and derive that the degree of AA is a simple nonlinear function of the Arctic and global feedbacks, the meridional heterogeneity in radiative forcing, and the partial sensitivities of AHT to global mean and meridional gradient of warming. The formula captures the varying AA in climate models and attributes the spread to models’ feedback parameters and AHT physics. The formula clearly illustrates how essential physics mutually determine the degree of AA and limits its range within 1.5-3.5. Our results articulate AHT as both forcing and feedback to AA, highlight its fundamental role in forming a baseline AA that exists even with uniform feedbacks, and underscore its partial sensitivities instead of its total change as key parameters of AA. The lapse-rate feedback has been widely recognized as a major contributor to AA but its effect is fully offset by the water-vapor feedback.
Abstract
The sensitivity of urban canopy air temperature (
T
a
) to anthropogenic heat flux (
Q
A
H
) is known to vary with space and time, but the key factors controlling such spatiotemporal ...variabilities remain elusive. To quantify the contributions of different physical processes to the magnitude and variability of
Δ
T
a
/
Δ
Q
A
H
(where
Δ
represents a change), we develop a forcing-feedback framework based on the energy budget of air within the urban canopy layer and apply it to diagnosing
Δ
T
a
/
Δ
Q
A
H
simulated by the Community Land Model Urban over the contiguous United States (CONUS). In summer, the median
Δ
T
a
/
Δ
Q
A
H
is around 0.01
K
W
m
−
2
−
1
over the CONUS. Besides the direct effect of
Q
A
H
on
T
a
, there are important feedbacks through changes in the surface temperature, the atmosphere–canopy air heat conductance (
c
a
), and the surface–canopy air heat conductance. The positive and negative feedbacks nearly cancel each other out and
Δ
T
a
/
Δ
Q
A
H
is mostly controlled by the direct effect in summer. In winter,
Δ
T
a
/
Δ
Q
A
H
becomes stronger, with the median value increased by about 20% due to weakened negative feedback associated with
c
a
. The spatial and temporal (both seasonal and diurnal) variability of
Δ
T
a
/
Δ
Q
A
H
as well as the nonlinear response of
Δ
T
a
to
Δ
Q
A
H
are strongly related to the variability of
c
a
, highlighting the importance of correctly parameterizing convective heat transfer in urban canopy models.
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