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Abstract This study examines December-January-February (DJF) soil moisture responses to multi-year (MY) and single-year (SY) La Niñas using a 2200-year CESM1 simulation, AGCM experiments, and observational data. Four regions where MY La Niñas amplify SY La Niñas’ impacts on soil moisture were identified: North America, Australia, the Middle East, and the Sahel. SY La Niñas typically cause soil moisture drying in the Middle East and North America and wetting in Australia and the Sahel. MY La Niñas enhance these effects in the second DJF due to the strengthening of precipitation anomalies or the accumulation of precipitation-induced soil moisture anomalies, except in the Sahel where wetting is driven in part by evapotranspiration anomalies. Soil moisture variations are linked to La Niña-induced sea surface temperature changes in the Indian Ocean (for Australia and the Middle East) and the Pacific Ocean (for North America). These amplified effects are largely supported by the observed MY La Niña events from 1948 to 2022. These findings emphasize the need to integrate MY La Niñas into regional agriculture and water resource management strategies to better anticipate and mitigate their impacts. 

Abstract Aegilops tauschii is the donor of the D subgenome of hexaploid wheat and a valuable genetic resource for wheat improvement. Several reference-quality genome sequences have been reported for A. tauschii accession AL8/78. A new genome sequence assembly (Aet v6.0) built from long Pacific Biosciences HiFi reads and employing an optical genome map constructed with a new technology is reported here for this accession. The N50 contig length of 31.81 Mb greatly exceeded that of the previous AL8/78 genome sequence assembly (Aet v5.0). Of 1,254 super-scaffolds, 92, comprising 98% of the total super-scaffold length, were anchored on a high-resolution genetic map, and pseudomolecules were assembled. The number of gaps in the pseudomolecules was reduced from 52,910 in Aet v5.0 to 351 in Aet v6.0. Gene models were transferred from the Aet v5.0 assembly into the Aet v6.0 assembly. A total of 40,447 putative orthologous gene pairs were identified between the Aet v6.0 and Chinese Spring wheat IWGSC RefSer v2.1 D-subgenome pseudomolecules. Orthologous gene pairs were used to compare the structure of the A. tauschii and wheat D-subgenome pseudomolecules. A total of 223 structural differences were identified. They included 44 large differences in sequence orientation and 25 differences in sequence location. A technique for discriminating between assembly errors and real structural variation between closely related genomes is suggested. 

Abstract This study explores the Antarctic sea ice concentration (SIC) response to multiyear (MY) and single-year (SY) El Niños using a 2200-yr CESM1 preindustrial simulation. During the first austral winter, MY El Niño weakens the amplitude of the typical SIC anomaly pattern induced by SY El Niño but maintains the same impact pattern. During the second winter, MY El Niños not only intensify the amplitude but also shift the typical impact pattern of SY El Niños eastward. The amplitude variation effect on SIC is caused by an Indian Ocean memory mechanism, while the zonal shifting effect on SIC pattern is caused by an Atlantic Ocean memory mechanism. These mechanisms result from the different responses of the two oceans to different locations and intensities between SY and MY El Niños. Observed MY El Niños during 1979–2020 confirm the distinct impacts during the second austral winter revealed by the CESM1 simulation. These results demonstrate that SIC in the Ross and Amundsen–Bellingshausen–Weddell Seas is sensitive to the SY or MY types of El Niño. 

Abstract Utilizing a 2200-yr CESM1 preindustrial simulation, this study examines the influence of property distinctions between single-year (SY) and multiyear (MY) La Niñas on their respective impacts on winter surface air temperatures across mid–high-latitude continents in the model, focusing on specific teleconnection mechanisms. Distinct impacts were identified in four continent sectors: North America, Europe, Western Siberia (W-Siberia), and Eastern Siberia (E-Siberia). The typical impacts of simulated SY La Niña events are featured with anomalous warming over Europe and W&E-Siberia and anomalous cooling over North America. Simulated MY La Niña events reduce the typical anomalous cooling over North America and the typical anomalous warming over W&E-Siberia but intensify the typical anomalous warming over Europe. The distinct impacts of simulated MY La Niñas are more prominent during their first winter than during the second winter, except over W-Siberia, where the distinct impact is more pronounced during the second winter. These overall distinct impacts in the CESM1 simulation can be attributed to the varying sensitivities of these continent sectors to the differences between MY and SY La Niñas in their intensity, location, and induced sea surface temperature anomalies in the Atlantic Ocean. These property differences were linked to the distinct climate impacts through the Pacific North America, North Atlantic Oscillation, Indian Ocean–induced wave train, and tropical North Atlantic–induced wave train mechanisms. The modeling results are then validated against observations from 1900 to 2022 to identify disparities in the CESM1 simulation. 

Abstract A 2,200‐year CESM1 pre‐industrial simulation is used to contrast Antarctic sea ice concentration (SIC) variations between the first and second austral winters of multi‐year La Niñas. The typical SIC anomaly pattern induced by single‐year La Niñas appears only during the second austral winter of multi‐year La Niñas. A similar pattern, but zonally shifted compared to the typical one, is found during the first winter and exhibits a tripolar pattern with anomaly centers over the Ross, Amundsen‐Bellingshausen, and Weddell Seas. The shift is a result of the pre‐onset conditions associated with multi‐year La Niñas that excites unique atmospheric circulation modes during the first winter. The distinct zonally‐shifted SIC anomaly pattern is observed in four of the six multi‐year La Niña events during the period 1979–2020. These results suggest that it is helpful to separate La Niñas into single and multi‐year events to better understand the La Niña impacts on Antarctic climate. 

Summary Cowpea (Vigna unguiculata[L.] Walp.) is a major crop for worldwide food and nutritional security, especially in sub‐Saharan Africa, that is resilient to hot and drought‐prone environments. An assembly of the single‐haplotype inbred genome of cowpea IT97K‐499‐35 was developed by exploiting the synergies between single‐molecule real‐time sequencing, optical and genetic mapping, and an assembly reconciliation algorithm. A total of 519 Mb is included in the assembled sequences. Nearly half of the assembled sequence is composed of repetitive elements, which are enriched within recombination‐poor pericentromeric regions. A comparative analysis of these elements suggests that genome size differences betweenVignaspecies are mainly attributable to changes in the amount ofGypsyretrotransposons. Conversely, genes are more abundant in more distal, high‐recombination regions of the chromosomes; there appears to be more duplication of genes within the NBS‐LRR and the SAUR‐like auxin superfamilies compared with other warm‐season legumes that have been sequenced. A surprising outcome is the identification of an inversion of 4.2 Mb among landraces and cultivars, which includes a gene that has been associated in other plants with interactions with the parasitic weedStriga gesnerioides. The genome sequence facilitated the identification of a putative syntelog for multiple organ gigantism in legumes. A revised numbering system has been adopted for cowpea chromosomes based on synteny with common bean (Phaseolus vulgaris). An estimate of nuclear genome size of 640.6 Mbp based on cytometry is presented.