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Accurately interpreting IPCC assessments

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 612-612, August 2024.

Remapping science

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 592-594, August 2024.

Explosive claim about ancient burials challenged

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 584-585, August 2024.

Eliminating a gut microbe could slash gastric cancers

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 585-586, August 2024.

Fire-against-fire HIV therapy passes key test in monkeys

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 586-587, August 2024.

In sweeping geological theory, mantle waves lift up plateaus

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 588-589, August 2024.

What’s killing lab yeast around the world?

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 589-589, August 2024.

Rich countries drain ‘shocking’ amount of labor

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 590-590, August 2024.

Deadlier strain of mpox spreads to multiple African countries

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 591-591, August 2024.

News at a glance

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 582-583, August 2024.

A new force emerges in genomics

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 595-599, August 2024.

Science should save all, not just some

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 581-581, August 2024.

Do small outdoor geoengineering experiments require governance?

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 600-603, August 2024.

In Science Journals

Science - Thu, 08/08/2024 - 05:56
Science, Volume 385, Issue 6709, Page 615-617, August 2024.

Comparison of the Occurrence Morphology of Phase Scintillation of GPS and Beidou Signals at Zhongshan Station, Antarctica

JGR:Space physics - Thu, 08/08/2024 - 05:20
Abstract

The characteristics of phase scintillation (represented by the phase scintillation indices, σφ) from GPS and Beidou are statistically analyzed using a ground-based receiver at Zhongshan Station, Antarctica, from 2020 to 2022 for the first time. The phase scintillation of the GPS and Beidou signals present a similar pattern of occurrence. The statistical results on the occurrence morphology of phase scintillation show that the phase scintillation predominately occurs in the magnetic pre-noon and pre-midnight sectors. Moreover, phase scintillation performs a dependence on solar and geomagnetic activities. Furthermore, the phase scintillation also gives a seasonal variation with the maximum occurrence happened at the autumn and the minimum occurrence during the summer. Consequently, these results improve understanding of the morphological characteristics of the phase fluctuations in the less studied Antarctic region. The study also demonstrates the use of the combined data set to improve the coverage in the Antarctic region.

Evaluation of Detection Efficiency of World Wide Lightning Location Network in Southeast Asian Region

JGR–Atmospheres - Wed, 08/07/2024 - 19:09
Abstract

The detection efficiency (DE) of the World Wide Lightning Location Network (WWLLN) is evaluated in Southeast Asia by comparing WWLLN data with the Earth Network Total Lightning Network (ENTLN) data taking into account time, distance, and peak-current parameters. The performance of WWLLN is evaluated in the months of November and December in two different years (2020–2021). These periods are selected to assess the change (if any) in DE overtime and the inclusion of new stations. The strokes between the two networks were considered matched if they fell within a time criterion of 100 µs and a location difference of 25 km. Using this criterion, 5.2 × 106 WWLLN strokes were matched with ENTLN cloud-to-ground (CG) lightning strokes in November-December 2020, resulting in a DE of 32.9%. Similarly, 4.6 × 106 WWLLN strokes were found to match in November-December 2021, yielding a DE of 36.5%. Analysis of the peak-currents reveals that DE is lowest (<10%) for a peak-current below ±10 kA. However, for peak-current exceeding ±50 kA, the DE increases to ∼60%. During November-December 2021, WWLLN reported 38.95 × 106 lightning strokes globally; amongst them, Dhaka station detected 0.5 × 106 strokes, contributing to a 1.3% increase in the global DE. Dhaka station detects most lightning strokes within 8 × 103 km, which diminishes to zero after 10 × 103 km. The Dhaka station recorded a larger number of strokes at longer detection distances during midnight (22:00–02:00) than during noon (10:00–14:00). The results signify a positive impact of the Dhaka station on WWLLN's DE during the mentioned period.

Assessing the Tropospheric Temperature and Humidity Simulations in CMIP3/5/6 Models Using the AIRS Obs4MIPs V2.1 Data

JGR–Atmospheres - Wed, 08/07/2024 - 18:39
Abstract

In this study, the Atmospheric Infrared Sounder (AIRS) Observations for Model Intercomparison Projects (Obs4MIPs) V2.1 tropospheric air temperature, specific humidity, and relative humidity data are utilized to evaluate the global tropospheric temperature and humidity simulations in the fully coupled global climate models from the Coupled Model Intercomparison Project phases 3, 5, and 6 (CMIP3, CMIP5, and CMIP6), and possible simulation improvement in CMIP6 models in comparison to CMIP3 and CMIP5 models. Our analyses indicate that all three phases of CMIP models share similar tropospheric air temperature, specific humidity, and relative humidity biases in their multi-model ensemble means relative to AIRS. Cold biases up to 4 K and positive relative humidity biases up to 20% are found in the free troposphere almost globally with maxima over the mid-latitude storm tracks. Warm biases up to 2 K are seen over the Southern Ocean in the lower troposphere. Positive specific and relative humidity biases exist over the off-equatorial oceans while negative specific and relative humidity biases are seen near the equator in the tropical free troposphere, which are related to the double-intertropical convergence zone bias in the models. Both the air temperature and specific humidity biases are important to the relative humidity biases except in the tropical free troposphere where the specific humidity biases dominate. The tropospheric air temperature, specific humidity, and relative humidity biases are reduced from CMIP3 to CMIP5 and to CMIP6 at almost all pressure levels except at 300 hPa for specific humidity and in the boundary layer for relative humidity.

kNNDM CV: k-fold nearest-neighbour distance matching cross-validation for map accuracy estimation

Geoscientific Model Development - Wed, 08/07/2024 - 18:28
kNNDM CV: k-fold nearest-neighbour distance matching cross-validation for map accuracy estimation
Jan Linnenbrink, Carles Milà, Marvin Ludwig, and Hanna Meyer
Geosci. Model Dev., 17, 5897–5912, https://doi.org/10.5194/gmd-17-5897-2024, 2024
Estimation of map accuracy based on cross-validation (CV) in spatial modelling is pervasive but controversial. Here, we build upon our previous work and propose a novel, prediction-oriented k-fold CV strategy for map accuracy estimation in which the distribution of geographical distances between prediction and training points is taken into account when constructing the CV folds. Our method produces more reliable estimates than other CV methods and can be used for large datasets.

An Independent Evaluation of GHGSat Methane Emissions: Performance Assessment

JGR–Atmospheres - Wed, 08/07/2024 - 18:25
Abstract

An independent evaluation of methane emissions data from GHGSat, a private company that operates a constellation of small microsatellites flying Fabry-Perot spectrometers operating at 1.6 µm, was performed. Data from multiple GHGSat commercial satellites, consisting of retrieved methane, diagnostics, and, where detected, plume and emissions information from roughly 250 scenes across Canada were analyzed. From these, 10 scenes contained methane plumes with a 2% detection rate for oil and gas scenes, and 10% for landfills. Methane precision was found to be 5%/2% on average for the C1/C2–C5 designs, with some variability due to scene albedo, terrain roughness, and airmass. Synthetic GHGSat plumes, generated using Lagrangian plume dispersion model and GHGSat characteristics, indicates typical detection limits of 240/180 kg/hr(C1/C2–C5), with a best case of roughly 100 kg/hr. Emissions and their uncertainties calculated using an alternative approach were in broad agreement with GHGSat-reported emissions. Overall, the performance of the GHGSat C2 design (also used for C3 onward) for favorable-viewing conditions was found to be largely consistent with company-advertised performance.

Transition of the Sun to a Regime of High Activity: Implications for the Earth Climate and Role of Atmospheric Chemistry

JGR–Atmospheres - Wed, 08/07/2024 - 18:15
Abstract

It was recently suggested that the Sun could switch to a high-activity regime which would lead to a rise of ultraviolet radiation with an amplitude of about four times larger than the amplitude of an average solar activity cycle and a simultaneous drop in total solar irradiance. Here, we applied the SOCOLv3-MPIOM model with an interacting ocean to simulate the response of chemistry, dynamics, and temperature of Earth's atmosphere to such a change in solar irradiance. We studied the effect of high activity regime on the atmosphere investigating the influence of the chemical and radiative processes on the climate, and chemistry of NOx, HOx, and O3. We find a climate cooling by up to 1K and a substantial increase in stratospheric ozone (up to 14%) and total ozone (up to 8%). To understand the role of the different processes we performed simulations with two sets of forcing accounting separately for the influence on chemical processes and for direct radiation energy balance. Our calculations show that the stratospheric O3 response is almost fully driven by the chemical processes. We also found that the direct radiation processes lead to near-surface cooling that results in the suppression of the Brewer-Dobson circulation. This, in turn, leads to the reduction of H2O influx from the low layers of the troposphere and to less intensive transport of ozone from the tropics to the middle latitudes. The surface climate response is dominated by direct radiation influence with only a small contribution from chemical processes.

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