Climate prediction of the seasonal sea-ice early melt onset in the Bering Sea

基于大尺度环流异常对海冰消融的影响过程,本文采用年际增量预测方法研制了白令海季节性海冰早期消融开始日期(EMO)的统计预测模型.预测模型选取了3个具有明确物理意义的预测因子:1月波弗特高压,前期11月东西伯利亚地区海平面气压,以及11月东欧平原积雪覆盖率。1月波弗特高压可以通过海气相互作用影响白令海地区海温异常,该海温异常能够从1月持续到3月,进而影响白令海EMO.11月东西伯利亚地区海平面气压与11月至次年2月北太平洋中纬度东部海温密切相关。伴随着北太平洋中纬度东部冷海温异常的出现,白令海地区会出现暖海温异常,进而导致白令海海冰范围减少,EMO较晚.1月北极偶极子异常是11月东欧平原积雪覆盖率影响次年白令海EMO的桥梁之一.1981-2022年的交叉检验结果表明:统计模型对白令海EMO具有较好的预测能力,预测与观测的EMO之间时间相关系数达到了0.45,超过了99%的置信水平.统计模型对白令海EMO正常年份和异常年份的预测准确率分别为60%和41%.

Early-season crop type mapping using 30-m reference time series

Early-season crop type mapping could provide important information for crop growth monitoring and yield prediction,but the lack of ground-surveyed training samples is the main challenge for crop type identification.Although reference time series based method(RBM)has been proposed to identify crop types without the use of ground-surveyed training samples,the methods are not suitable for study regions with small field size because the reference time series are mainly generated using data set with low spatial resolution.As the combination of Landsat data and Sentinel-2 data could increase the temporal resolution of 30-m image time series,we improved the RBM by generating reference normalized difference vegetation index(NDVI)/enhanced vegetation index(EVI)time series at 30-m resolution(30-m RBM)using both Landsat and Sentinel-2 data,then tried to estimate the potential of the reference NDVI/EVI time series for crop identification at early season.As a test case,we tried to use the 30-m RBM to identify major crop types in Hengshui,China at early season of 2018,the results showed that when the time series of the entire growing season were used for classification,overall classification accuracies of the 30-m RBM were higher than 95%,which were similar to the accuracies acquired using the ground-surveyed training samples.In addition,cotton,spring maize and summer maize distribution could be accurately generated 8,6 and 8 weeks before their harvest using the 30-m RBM;but winter wheat can only be accurately identified around the harvest time phase.Finally,NDVI outperformed EVI for crop type classification as NDVI had better separability for distinguishing crops at the green-up time phases.Comparing with the previous RBM,advantage of 30-m RBM is that the method could use the samples of the small fields to generate reference time series and process image time series with missing value for early-season crop casification;while,samples collected from multiple years should be futher used so that the reference time series could contain more crop growth conditions.

Performance of Soft Rice (Oryza sativa L.) Grown in Early Season in China

Eating quality is of paramount importance to rice(Oryza sativa L.)consumers and soft rice with low amylose content has become popular in China.This study was conducted to evaluate the performance of soft rice grown in the early season(ES)dominated by non-soft rice.Field experiments were conducted in Yongan and Santang,Hunan Province,China from 2016-2018.Results showed that grain amylose content in soft rice cultivars was consistently lower in the ES compared to the late season(LS).The lower grain amylose content in the ES compared to the LS was partly attributed to higher average daily mean temperature during grain filling.No significant relationship was observed between grain yield and seed amylose content in ES rice.Soft rice cultivars produced a similar average grain yield to non-soft rice cultivars in the ES.These results encourage breeders to develop more ES rice cultivars with soft texture to meet the consumer demand for this type of rice.

Do Birth Season and Sex Affect Adult Lung Function as Early Life Factors?

Objectives: Although lung function decline is a normal ageing process, it can be potentiated by risk factors. However, the potential impact of early life factors on lung function decline has been scarcely studied. The aim of this study was to investigate the potential correlation between birth season and adult lung function. Methods: We enrolled 1008 South Korean patients (530 men and 478 women;age range, 40 - 80 years) who were hospitalized for urological surgery, irrespective of respiratory disease. All patients underwent the pulmonary function test before any surgery or procedure. Based on their birth season, the patients were divided into two groups (spring, summer, and fall vs. winter). Results: Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and FEV1 % predicted of men born in winter were lower than those of men born in other seasons. Univariate and multivariate analyses using linear regression models also showed that birth season was a significant predictive factor for FVC, FEV1, and FEV1 % predicted in men. However, birth season was not correlated with lung function in women. Among male ever-smokers, FEV1 and FEV1 % predicted were lower for men born in winter than for those born in other seasons. Conclusions: Unlike women, men born in winter had lower lung function than did men born in other seasons. These results suggest that birth season might be an early life factor that predicts airway function. Furthermore, birth season has different effects on adult lung function depending on the patient’s sex.

Erratum to: Implications from Subseasonal Prediction Skills of the Prolonged Heavy Snow Event over Southern China in Early 2008

In the original publication of this article,the blue lines(PCC skill of 500-hPa geopotential height over mid-high latit-udes between the observation and ECWMF)in Fig.8a was misplaced.The correct Fig.8 is shown below.The associated description of“other than in P2−P3”should be“other than in P2”in section 3.3.Neither the abstract nor the conclusions are impacted.

Abnormal Karyotype of Pen Shell (Atrina pectinata) During Its Early Embryonic Development in Late Breeding Season

The pen shell,Atrina pectinata,distributes globally.It is one of the most important edible bivalves in east Asian countries.However,there are multiple difficulties in rearing pen shell larvae and juveniles because of their high mortality.To understand the mechanism underlining such high mortality at the early embryonic development stage,we obtained approximately 100 million larvae during later breeding season in June,2017,and checked a large amount of mitotic chromosomal plates of the early embryos and post-spawning gonads tissue slices of their parents.The results showed that most diploid A.pectinata embryos have 17 pairs of chromosomes(2n=34)as their parents do.The first pair of particularly large chromosomes are heterotypic in some diploid embryos while they are homomorphic in others.The primary sex-determination chromosome type is XX/XY.A lot of triploid,pentaploid and aneuploid embryos with different numbers of the largest homomorphic or heteromorphic chromosomes were found due to the degeneration of overmatured parent gonads which hold normal karyotype.These larvae will die even though most of them may develop into the trochophore stage with 34 chromosomes.Genetic deficiency of chromosomes will cause a high rate of mortality in early embryos in late breeding season.These findings should enrich the current knowledge of juvenile pen shell aquaculture.

ON STRONG SIGNALS OF MONTHLY PRECIPITATION ANOMALIES IN EARLY RAINING SEASON OF GUANGDONG AND CONCEPTUAL MODELS OF PREDICTION

Reanalysis data from NCEP/NCAR are used to systematically study preceding signals of monthly precipitation anomalies in the early raining season of Guangdong province, from the viewpoints of 500-hPa geopotential height field, outgoing longwave radiation (OLR) field, sea surface temperature (SST) and fourteen indexes of general circulation depicting atmosphere activity at high, middle and low latitutes. Being multiple tools of information, a number of conceptual models are formulated that are useful for prediction of the magnitude of monthly precipitation (drought, flood and normal conditionss).

Simulation of Potential Productivity of Early Season Rice Varieties in Different Reqions of South China

Rice is a staple food crop in China.Since the 1950’s,many new varieties havebeen used and resulted in great increase ofyield.However there were still some barriersin the nationwide extension of new varietiesdue to the insufficient information about thecharacteristics of varieties.So,it is impor-tant to find ways of determining the potential

NUMERICAL STUDY OF THE EFFECTS OF PERSISTENT WARMER SEA SURFACE TEMPERATURE IN TROPICAL INDIAN OCEAN ON ATMOSPHERIC CIRCULATION IN THE EARLY SUMMER IN EAST ASIA IN 1991

By employing the CCM1(R15L12)long-range spectral model, study is undertaken of the effects of sea surface temperature anomaly(SSTA) for tropical Indian ocean on circulation transformation in the early summer in East Asia in 1991. The results indicate that warmer SSTA contributes to the increasing of the temperature over the Plateau in early summer, resulting in the intensification of tropical easterly jet on 100 hPa and northward shift of Northern Hemisphere subtropical westerly jet in May. It is obviously favorable for the subtropical high enhancement over western Pacific Ocean in May and subtropical westerly jet maintaining at 35～40 °N in June, making the Mei-Yu come earlier and stay over the Changjiang basin in 1991. Furthermore, warmer SSTA is also advantageous to averaged temperature rise in East Asia land region and Nanhai monsoon development. These roles are helpful in accelerating the seasonal transition for East Asia in early summer.

华南地区早晚兼用型水稻产量和氮素吸收在早、晚季的差异特征

为明确华南双季稻区早晚兼用型水稻产量和氮素吸收在早、晚季的差异特征,以6个早晚兼用型水稻品种为试验材料,按当地高产栽培条件在早、晚季种植,测定其产量、产量构成、干物质积累和氮素吸收等。结果表明,早晚兼用型水稻在早、晚季种植时产量分别为6.68~7.91 t/hm^(2)和5.72~6.11 t/hm^(2);早季产量显著高于晚季,平均增幅为1.53 t/hm^(2)。相关分析表明,较高的早季产量与其有效穗数和粒重的提高有关。早、晚季干物质积累量和氮素吸收差异显著;相对于晚季,早季成熟期干物质积累量和氮素吸收平均提高25.0%和29.5%。另外,早、晚季产量与其干物质积累量和氮素吸收显著正相关。早晚兼用型水稻在早季种植时具有较高的产量、物质生产和氮素吸收能力。研究结果可为华南地区早晚兼用型水稻的丰产栽培提供理论依据。

华南双季稻区不同季别种植籼稻品种整精米率差异及高整精米率材料筛选

整精米率是决定稻米商品价值的重要性状之一,筛选不同环境条件下种植都具有高整精米率的品种具有重要意义。本研究通过比较357个籼稻种质在广东省农业科学院大丰试验基地不同年份(2021—2023)不同季节(早、晚季)种植时的整精米率,发现2021年晚季的整精米率最好、2022年早季次之、2023年早季最差。其中,泰丰B、19香、广恢6200、粤黄丝苗、华新占、香雪丝苗等17份长粒籼稻的整精米率在3次不同种植环境下均达GB/T17891—2017优质稻标准,适用于高整精米率水稻育种。

不同播期下高温对江西早稻灌浆结实及产量的影响

以江西主栽常规籼稻品种为试验材料,于2022年在南昌县进行分期播种试验,4个播期分别为3月11日(B1)、3月24日(B2,常规播期)、4月5日(B3)和4月15日(B4),分析大田高温对早稻抽穗、灌浆及产量的影响,以历史气象数据(1961-2022年)对不同播期下的高温发生情况进行对比分析。结果表明:随着播期推迟,早稻产量、结实率和千粒重均呈下降趋势,高温日数与产量、结实率、千粒重呈显著负相关关系(P<0.05),3月11日播期下,早稻产量显著高于3月24日及以后各播期处理。高温虽提高了早稻抽穗后10~15d灌浆速率,但不利于抽穗15d后较高灌浆速率的维持。4个播期下早稻生育期内,1961-2022年早稻灌浆期高温日数B4播期明显高于B1;2000年后各播期处理生育期内早稻抽穗灌浆期高温日数呈明显增加趋势;江西早稻高温易发区与早稻主要种植区高度重合。江西早稻种植区可适当提早播种,以减轻高温带来的不利影响。

基于DSSAT模型模拟气候变化对江西双季稻生长期和产量的影响

江西是中国双季稻的主要种植地区。气候变化严重影响了双季稻生产。基于江西省1981—2022年逐日气象资料和双季稻作物资料,对DSSAT模型进行调参验证;利用验证后的DSSAT模型,分析江西省双季稻生长期和产量空间分布和时间变化趋势;采用t检验方法,明确气候变化对江西早稻和晚稻的影响差异。结果表明:(1)江西早稻(晚稻)播种期至开花期天数、播种期至成熟期天数和产量模拟值与观测值的归一化均方根误差分别为1.87%(1.86%)、2.05%(2.36%)和6.05%(7.30%),D指标分别为0.97(0.98)、0.96(0.96)和0.95(0.94);(2)固定播期和品种条件下,1981—2022年江西早稻和晚稻生长期均呈显著缩短趋势,平均每10年分别减少2.22 d和1.61 d;研究期间江西早稻和晚稻潜在产量均呈显著下降趋势,平均每10年分别减少181.30 kg hm^(-2)和276.16 kg hm^(-2);(3)t检验表明,江西早稻生长期气候倾向率极显著地小于晚稻,而江西早稻潜在产量气候倾向率极显著地大于晚稻。DSSAT模型可较好的模拟江西双季稻生长发育和产量。气候变化对江西早稻生长期和晚稻潜在产量影响更加明显。本研究为江西双季稻作物模型研究、产量预报和气候变化评估提供了科学依据。

西藏气候季节早晚和长短等级划分指标

为了更好地了解全球气候变化背景下,高海拔地区季节变化对生态和环境的响应机制,研究西藏季节早晚和长短等级划分指标变得尤为重要。根据1981—2023年西藏地区38个气象站点气温日资料,选择四季划分气温阈值6℃、17℃、17℃、6℃,探讨气候季节早晚和长短等级划分指标及其演变规律。结果表明:(1)38站春、夏、秋、冬四季开始日期平均出现在4月21日、6月17日、7月17日、10月17日,时间长度平均为56 d、29 d、92 d、188 d。(2)当年气候季节起止时间、时间长度整体上呈现“冬季标准差最小、夏季标准差最大”的特征。(3)气候季节起止时间、时间长度早晚等级呈现“正常等级天数>略偏早晚、偏早晚等级天数>显著早晚、异常早晚等级天数”的特点,A指标更符合早晚和长短等级划分指标的阈值。(4)西藏地区春夏季的开始日期有提前的趋势,秋冬季则有推迟的趋势。(5)春季开始日期、冬季结束日期、夏季时间长度以正常等级为主,夏秋冬季开始日期、春秋季结束日期以早等级为主,春秋季时间长度以短等级为主,冬季时间长度以长等级为主,夏季结束日期以晚等级为主。研究结果可为气候资源管理、生态环境保护、人类生产生活等提供参考。

基于CNN-BiLSTM-Attetion的银杏液流预测模型及环境因子影响研究

树木液流受生理活动和多重环境因子的共同作用,表现为非线性和随机性特征,为预测模型的精确度带来挑战。对此,结合CNN卷积层、BiLSTM双向网络结构和注意力机制的优势分别对树干液流序列的局部特征、长期依赖和关键信息进行提取,并根据自测银杏液流数据集构建基于CNN-BiLSTM-Attetion的树干液流预测模型。该模型的R^(2)、MSE和MAE分别为0.9773、0.0029和0.0134,相较于CNN、BiLSTM、XGBoost、RNN和TCN建立的模型均有不同程度的提高。另外,还利用特征工程对环境因子的重要性进行排名,分析银杏树干液流在生长季初期对环境因子的响应规律,对银杏生长季初期的灌溉和养护提供理论依据。

早稻中后期病虫害发生与防治

早稻中后期是各类病虫害发生为害的高发期,若发现不及时、防治不科学,会对早稻产量及品质产生较大的影响,严重的甚至会颗粒无收,造成巨大经济损失,做好早稻中后期病虫害防治工作尤为关键。以宾阳县为例,对早稻中后期主要病虫害发生特点及综合防治策略展开研究。

非典型大西洋尼诺对中国东部前、后汛期降水的影响

采用1979—2020年共42 a的降水观测和再分析资料,使用多变量EOF、傅立叶滤波、线性回归、T-N波通量等方法,研究了非典型大西洋尼诺(Non-Canonical Atlantic Ni1o,NCA)对中国东部夏季前、后汛期降水的影响及物理机制。结果显示,NCA在前汛期引起中国南方降水增加,但在后汛期导致华南沿海地区降水减少而北方降水增加。这是由于在前汛期,NCA的暖海温异常位于热带北大西洋,可通过“风-蒸发-海表温度”正反馈引起拉尼娜,进而激发西北太平洋异常反气旋,其西北侧的异常西南气流有助于将暖湿水汽输送至我国南方,导致前汛期南方降水增加。在后汛期,NCA的暖海温异常南移至赤道大西洋,通过调节沃克环流增强拉尼娜,使得西北太平洋异常反气旋进一步增强并覆盖华南地区,导致华南降水减少而北方降水增加。此外,与NCA相关的东传罗斯贝波列在前/后汛期位于副热带/中高纬地区,其在我国东部引起的环流异常也有助于NCA在前/后汛期影响我国南/北方降水。

双季稻区“晚稻品种连种”模式:内涵界定、产生逻辑与实现路径——以江西省为例

双季稻区稳定粮食生产的关键在于早稻,但早稻生产长期呈现“低质低效”“增产不增收”的典型特征,导致农户种植积极性下降,“双改单”甚至“稻改经”现象突出。“十三五”以来,江西创新和大力示范推行“晚稻品种连种”模式,取得了明显成效,促进了双季稻区早稻高质高效发展。但推行中也存在适用品种缺乏、龙头企业带动不强、产业链条延伸不足、缺乏完善的配套设施服务支撑、市场接受程度有待提高等困难与问题。为此,提出加快“晚稻早种”适用品种选育、加强技术集成示范推广,深化农业产业链建设、加强龙头企业带动作用,完善农机社会化服务体系建设,发挥“有为政府”与“有效市场”协同作用、提高“晚稻品种连种”模式的市场接受度等对策建议。

稻螟赤眼蜂防治早稻一代二化螟的应用技术

为明确稻螟赤眼蜂防治早稻一代二化螟的田间高效释放应用技术,于2017—2018年在宁波市镇海和奉化两地开展了不同放蜂起始时间、放蜂量和放蜂次数及与化学防治结合应用对早稻田一代二化螟的控害效果试验。结果表明,二化螟发蛾初期、蛾始盛期和蛾盛期3个不同时期中从蛾始盛期开始放蜂的防治效果最好,防治效果为54.06%;在放蜂次数不变的前提下,667 m^(2)放蜂总量4万头和5万头处理对二化螟的防治效果分别为65.65%和67.32%,均显著高于3万头处理的防治效果,但两者差异不显著;在放蜂总量不变的前提下,放蜂3次和放蜂4次处理的防治效果也均显著高于放蜂2次的防治效果,但两者也无显著性差异;放蜂3次后再化学防治1次能显著提高对二化螟的综合防治效果,其防效与化学防治2次的防治效果相当。因此,在应用稻螟赤眼蜂防控早稻一代二化螟时,应根据越冬代二化螟的实际发生情况来确定合理的放蜂时间、放蜂量和放蜂次数,以确保赤眼蜂的释放控害技术措施经济高效。

黄河下游凌汛期防凌现状及对策研究

为了研究黄河下游凌汛期防凌现状,采取针对性防治策略,通过对黄河下游凌汛期的实地考察、数据分析及文献研究,分析当前防凌工作面临的问题。黄河下游凌汛期气温变化大是导致凌情不稳定、河道淤积影响行凌的重要原因。现有防凌措施在监测预警、工程调度等方面取得了一定成效,但仍需进一步完善。研究表明,为更好地应对黄河下游凌汛期挑战,应提高监测预警技术水平,加强工程设施建设与维护,提高应急处置能力,加大资金投入力度,以确保黄河下游凌汛期的安全。