涓流細(xì)雨

編輯 賈朋群

“Himawari-8 is sending kinds of big data that were not available before. We are now able to build a system that uses those data to improve the way we predict weather. The strength of this system is it gives you accurate weather predictions when natural disasters may happen, and it is updated constantly. For those who are vulnerable to natural disasters, like the elderly and people with disabilities, you want to give them enough time if they have to evacuate their home.”

“葵花-8”衛(wèi)星獲得了以前無(wú)法得到的大數(shù)據(jù)。我們現(xiàn)在能夠基于這些數(shù)據(jù)建立改進(jìn)天氣預(yù)報(bào)的系統(tǒng)，系統(tǒng)定時(shí)更新。對(duì)于面對(duì)自然災(zāi)害脆弱的人群，如老人和殘疾人，需要從家中轉(zhuǎn)移時(shí)就能得到更多的時(shí)間?！?/p>

——日本理化研究所利用“葵花-8'衛(wèi)星建立的“紅外輻射亮度數(shù)據(jù)',可用于天氣預(yù)報(bào)模式,主要能夠提供濃云密布時(shí)天氣系統(tǒng)的分布,從而改變之前這類(lèi)天氣難以有效處理的問(wèn)題。該項(xiàng)目的負(fù)責(zé)人Takemasa Miyoshi描述了這個(gè)項(xiàng)目可能獲得的結(jié)果。

“The rapid and dramatic changes we continue to see in the Arctic present major challenges and opportunities. This year’s Arctic Report Card is a powerful argument for why we need longterm sustained Arctic observations to support the decisions that we will need to make to improve the economic well-being for Arctic communities, national security, environmental health and food security.”

“我們看到的北極快速和強(qiáng)烈的變化帶來(lái)了巨大的挑戰(zhàn)和機(jī)會(huì)。今年的《北極報(bào)告》有力地支持了我們?yōu)槭裁葱枰L(zhǎng)期可持續(xù)的北極觀測(cè)來(lái)支持決策，我們需要這些決策改進(jìn)北極周邊經(jīng)濟(jì)狀況、國(guó)家安全、環(huán)境健康和糧食安全?！?/p>

——美國(guó)NOAA連續(xù)第12年發(fā)布《北極報(bào)告》,這份由12個(gè)國(guó)家85位學(xué)者共同完成并且通過(guò)同行評(píng)議定稿的報(bào)告指出,2017年是北極有記錄以來(lái)第二高溫年,升溫幅度是全球的兩倍。談到這份報(bào)告的價(jià)值,NOAA執(zhí)行局長(zhǎng)Gallaudet博士如是說(shuō)。

“Events like these cause enormous damage. It’s important that we have an accurate understanding of how the hazard posed by these events change as the climate changes.”

“這樣的事件引發(fā)巨大損失。我們認(rèn)識(shí)當(dāng)氣候變化發(fā)生時(shí)這些事件的改變是如何帶來(lái)災(zāi)害的就非常重要?！?/p>

——2017年大西洋颶風(fēng)季,成為美國(guó)歷史上最具破壞力的颶風(fēng)季節(jié),在11月30日官方颶風(fēng)季尚未結(jié)束,損失已經(jīng)超過(guò)了2000億美元。哥倫比亞大學(xué)氣候?qū)W者開(kāi)發(fā)了新的全球颶風(fēng)模式,能夠估計(jì)罕見(jiàn)和高影響風(fēng)暴在不同氣候背景下的長(zhǎng)期損失。項(xiàng)目負(fù)責(zé)人,該校氣候和社會(huì)國(guó)際研究所的Chia-Ying Lee闡述了他們這項(xiàng)研究的意義所在。

2017年11月舉行的UCAR國(guó)會(huì)吹風(fēng)會(huì)上，來(lái)自美國(guó)高校、聯(lián)邦實(shí)驗(yàn)室和私企的專(zhuān)家，面對(duì)每年數(shù)十億天氣相關(guān)的市場(chǎng)，就吹風(fēng)會(huì)主題“研究向產(chǎn)業(yè)過(guò)渡（MOVING RESEARCH TO INDUSTRY）”發(fā)表了各自就天氣預(yù)報(bào)技術(shù)、政府投入和天氣市場(chǎng)等的觀點(diǎn)。

“Thanks to a quiet revolution in modern weather prediction,we can all use forecasts to make decisions in ways that wouldn't have been possible just 10 years ago. Now we are looking to the next revolution, which includes giving people longer lead times and communicating risk as effectively as possible.”

“源于現(xiàn)代天氣預(yù)報(bào)靜悄悄的革命，我們所有人利用預(yù)報(bào)進(jìn)行決策的方式在10年前是不可能的?，F(xiàn)在我們關(guān)注下一場(chǎng)革命，包括讓公眾有更長(zhǎng)的提前時(shí)間以及盡可能有效的風(fēng)險(xiǎn)告知?！?/p>

——NCAR資深學(xué)者,該機(jī)構(gòu)MMM實(shí)驗(yàn)室副主任Rebecca Morss發(fā)表了自己的看法。

“The future of weather forecasting is very promising. With strategic investments in observations, modeling, data assimilation,and supercomputing, we will see some remarkable achievements.”

“未來(lái)天氣預(yù)報(bào)非常值得期待。在觀測(cè)、模擬、數(shù)據(jù)同化和超級(jí)計(jì)算方面的投入，能讓我們獲得明顯的進(jìn)展?！?/p>

——賓州州立大學(xué)氣象和統(tǒng)計(jì)學(xué)教授Fuqing Zhang在強(qiáng)調(diào)了科學(xué)家正在借助更詳盡觀測(cè)和計(jì)算模擬,特別是利用NOAA的GOES-R衛(wèi)星和強(qiáng)有力的FV3模式推進(jìn)對(duì)颶風(fēng)和其他風(fēng)暴的認(rèn)識(shí)后,給出了他的展望。

“We have a weather and climate enterprise that we can be extremely proud of as a nation, but it's not where it should be.Weather affects every consumer and business, and the public-private partnership can play a pivotal role in providing better weather information that is critically needed.”

“我們?yōu)閲?guó)家的天氣和氣候事業(yè)非常驕傲，但是不應(yīng)停止于此。天氣影響每個(gè)消費(fèi)者和商業(yè)，公共—私人伙伴在提供更好的所需天氣信息方面起到重要作用。”

——美國(guó)天氣公司科學(xué)和預(yù)報(bào)業(yè)務(wù)主任Mary Glackin如是說(shuō)。他認(rèn)為天氣企業(yè)界的目標(biāo)是幫助消費(fèi)者和業(yè)界做出更好的決策,這可以通過(guò)提供自己做出的預(yù)報(bào)和傳送國(guó)家氣象局預(yù)警兩個(gè)渠道實(shí)現(xiàn)。天氣公司目前正在調(diào)整基于NCAR的模式,即MPAS (Model for Prediction Across Scales,跨尺度模式)模式用于全球?qū)崟r(shí)天氣預(yù)報(bào)。

“These essential collaborations between government agencies,universities, and private companies are driving landmark advances in weather forecasting. The investments that taxpayers are making in basic research are paying off many times over by keeping our nation safer and more prosperous.”

“這些在政府部門(mén)、大學(xué)和私企之間關(guān)鍵的合作正在促成天氣預(yù)報(bào)的重大進(jìn)展。納稅人在基礎(chǔ)研究上的投入，可以通過(guò)保持國(guó)際安全和更加繁榮得到數(shù)倍的回報(bào)?！?/p>

——NCAR主席Antonio Busalacchi,強(qiáng)調(diào)了多方合作代理的益處,指出NSF、NOAA和其他聯(lián)邦機(jī)構(gòu)對(duì)研究投入對(duì)于改進(jìn)預(yù)報(bào)十分關(guān)鍵。

2018年初召開(kāi)的美國(guó)氣象學(xué)會(huì)第98屆年會(huì)上，首次舉辦的“小衛(wèi)星地球觀測(cè)第一次學(xué)術(shù)會(huì)”（First Conference on Earth Observing SmallSats）引入注目。會(huì)議安排的30個(gè)報(bào)告，分“立方體衛(wèi)星和小衛(wèi)星在推進(jìn)地球科學(xué)、天氣預(yù)報(bào)、空間天氣預(yù)報(bào)、水文研究和氣候監(jiān)測(cè)中的進(jìn)展”（Advances in CubeSats and SmallSats to Improve Earth Science,Weather Forecasting, Space Weather Prediction,Hydrology Studies, or Climate Monitoring）、“觀測(cè)系統(tǒng)理念”（Observing System Concepts）和“可行技術(shù)及其成熟”（Enabling Technologies and Their Maturation）和“小衛(wèi)星地球觀測(cè)：新常態(tài)”（Earth Observing SmallSats: The New Normal）等4個(gè)主題（其中，第2、3個(gè)主題為與第22屆衛(wèi)星氣象和海洋學(xué)會(huì)議聯(lián)合舉辦），全面評(píng)述了小衛(wèi)星在地球觀測(cè)領(lǐng)域里的優(yōu)勢(shì)、技術(shù)開(kāi)發(fā)細(xì)節(jié)和一些項(xiàng)目規(guī)劃在未來(lái)可能展示的作用。這里介紹幾位來(lái)自NASA的參會(huì)學(xué)者的發(fā)言。

“RainCube (Radar in a CubeSat) is a technology demonstration mission to enable Ka-band precipitation radar technologies on a low-cost, quick-turnaround platform. Radar instruments have often been regarded as unsuitable for small satellite platforms due to their traditionally large size, weight, and power. The Jet Propulsion Laboratory has developed a novel radar architecture compatible with the 6U form factor. The RainCube mission will validate two key technologies in the space environment – a miniaturized Ka-band precipitation pro filing radar that occupies ～3U and a 0.5m Ka-band deployable parabolic antenna stowed within 1.5U.”

“RainCube（即立方體衛(wèi)星上的雷達(dá)）技術(shù)，展示了Ka波段降水雷達(dá)技術(shù)可以應(yīng)用于低造價(jià)和快速轉(zhuǎn)向的平臺(tái)。雷達(dá)設(shè)備一直被認(rèn)為不適宜小衛(wèi)星平臺(tái)，因?yàn)閭鹘y(tǒng)上該設(shè)備具有大尺寸、大重量和大能耗。JPL研發(fā)了新的雷達(dá)架構(gòu)可以裝入6U空間。RainCube項(xiàng)目驗(yàn)證了兩項(xiàng)空間環(huán)境下的關(guān)鍵技術(shù)：小型化的Ka波段降水廓線雷達(dá)占據(jù)3U空間和一個(gè)0.5 m的Ka波段可展開(kāi)的拋物形天線可放入1.5U的空間內(nèi)。”

——來(lái)自NASA噴氣推進(jìn)實(shí)驗(yàn)室(JPL)的Shivani S Joshi在會(huì)上詳細(xì)解釋了RainCube項(xiàng)目,預(yù)計(jì)該衛(wèi)星將在2018年5月送往國(guó)際空間站,7月送入軌道。

“The CubeSat Infrared Atmospheric Sounder (CIRAS)employs an MWIR spectrometer operating from 4.08-5.13 μm with 625 channels and spectral resolution of 1.2-2.0 cm-1to achieve lower tropospheric temperature and water vapor profiles. The CIRAS is packaged in a 6U CubeSat and uses less than 14 W. CIRAS is under development at NASA JPL and scheduled for launch in 2019.CIRAS technology can be applied to a future Earth Observing Nanosatellite (EON)-Infrared, to address a loss or gap in coverage of CrIS on orbit.”

“立方體衛(wèi)星紅外大氣探測(cè)器（CIRAS）采用MWIR分光儀，工作譜段為4.08～5.13 μm，擁有625個(gè)頻道，空間分辨率為1.2～2.0 cm-1，可獲得對(duì)流層低層溫度和水平廓線。CIRAS裝入6U立方體衛(wèi)星，能耗小于14 W。目前CIRAS在NASA JPL開(kāi)發(fā)，計(jì)劃2019年發(fā)射。CIRAS技術(shù)可以在未來(lái)地球觀測(cè)超小衛(wèi)星（EON）—紅外項(xiàng)目中應(yīng)用，作為在軌的CrIS的備份或補(bǔ)足其覆蓋的不足?！?/p>

——同樣來(lái)自JPL的Thomas Pagano則在討論了紅外譜段探測(cè)對(duì)于大氣科學(xué)研究和氣象預(yù)報(bào)、氣候變化監(jiān)測(cè)等的重要意義后,以CIRAS 項(xiàng)目為例,說(shuō)明紅外探測(cè)技術(shù)也可以通過(guò)小衛(wèi)星平臺(tái)來(lái)實(shí)施,且對(duì)于未來(lái)地球觀測(cè)體系的設(shè)計(jì)也具有重要意義。

“The National Aeronautics and Space Administration (NASA)Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) mission is a constellation of state-of-the-science observing platforms that will measure temperature and humidity soundings and precipitation with spatial resolution comparable to current operational passive microwave sounders but with unprecedented temporal resolution.TROPICS is a cost-capped ($30M) Venture-class mission funded by the NASA Earth Science Division. The mission is comprised of a constellation of 3 unit (3U) SmallSats, each hosting a 12-channel passive microwave spectrometer based on the Micro-sized Microwave Atmospheric Satellite 2 (MicroMAS-2) developed at MIT LL. TROPICS will provide imagery near 91 and 205 GHz,temperature sounding near 118 GHz, and moisture sounding near 183 GHz. Spatial resolution at nadir will be around 27 km for temperature and 17 km for moisture and precipitation. The swath width is approximately 2000 km. TROPICS enables temporal resolution similar to geostationary orbit but at a much lower cost,demonstrating a technology that could impact the design of future Earth-observing missions. The TROPICS satellites for the mission are slated for delivery to NASA in 2019 with potential launch opportunities in 2020. The primary mission objective of TROPICS is to relate temperature, humidity, and precipitation structure to the evolution of tropical cyclone (TC) intensity.”

“NASA的小衛(wèi)星星座降水結(jié)構(gòu)和風(fēng)暴加強(qiáng)時(shí)間解析觀測(cè)（TROPICS）項(xiàng)目是一個(gè)科學(xué)領(lǐng)先的衛(wèi)星星座觀測(cè)平臺(tái)，將以空間分辨率等同于目前業(yè)務(wù)被動(dòng)微波探測(cè)和空前的時(shí)間分辨率實(shí)施溫度、濕度和降水探測(cè)。TROPICS是NASA地球科學(xué)部資助的成本設(shè)定（3000萬(wàn)美元）的企業(yè)級(jí)項(xiàng)目，項(xiàng)目包括一個(gè)含有3個(gè)單位（3U）小衛(wèi)星的星座，每個(gè)小衛(wèi)星載有一個(gè)在MIT LL開(kāi)發(fā)的基于MicroMAS-2的12通道被動(dòng)微波光譜儀，將提供91和205 GHz附近的圖像、118 GHz附近的溫度探測(cè)和183 GHz附近的濕度。星下點(diǎn)空間分辨率溫度為27 km，水汽和降水為17 km，掃描帶的寬度約2000 km。TROPICS的時(shí)間分辨率類(lèi)似與地球靜止軌道，但費(fèi)用低很多，顯示出是對(duì)未來(lái)地球觀測(cè)設(shè)計(jì)可能產(chǎn)生影響的技術(shù)。NASA計(jì)劃于2019年或2020年發(fā)射TROPICS衛(wèi)星。TROPICS的主要任務(wù)目標(biāo)，是熱帶氣旋（TC）加強(qiáng)時(shí)的溫度、濕度和降水結(jié)構(gòu)演化。”

——來(lái)自NASA馬歇爾太空飛行中心(MSFC)的Bradley T. Zavodsky關(guān)注的針對(duì)熱帶TC加強(qiáng)的小衛(wèi)星觀測(cè)項(xiàng)目,讓小衛(wèi)星項(xiàng)目走向面對(duì)需求進(jìn)行設(shè)計(jì)和實(shí)施。

“Cloud ice plays important roles in Earth’s energy budget and cloud-precipitation processes. Knowledge of global cloud ice and its properties is critical for understanding and quantifying its roles in Earth’s atmospheric system. It remains a great challenge to measure these variables accurately from space. Submillimeter (submm) wave remote sensing has capability of penetrating clouds and measuring ice mass and microphysical properties. In particular, the 883-GHz frequency is a highest spectral window in microwave frequencies that can be used to fill a sensitivity gap between thermal infrared (IR)and mm-wave sensors in current spaceborne cloud ice observations.IceCube is a cubesat spaceflight demonstration of 883-GHz cloud radiometer technology. Its primary objective is to raise the technology readiness level (TRL) of 883-GHz cloud radiometer for future Earth science missions.”

“云冰在地球能量收支和云—降水過(guò)程中起重要作用，全球云冰及其屬性的知識(shí)對(duì)于認(rèn)識(shí)和量化其在地球大氣系統(tǒng)中的作用十分關(guān)鍵。從空間準(zhǔn)確測(cè)量這些變量還是巨大挑戰(zhàn)。亞毫米（submm）波遙感能夠穿透云測(cè)量冰體及微物理屬性。特別是，883 GHz頻率是毫米頻率中的最高譜窗，可用來(lái)填補(bǔ)目前天基云冰觀測(cè)從熱紅外（IP）到毫米波傳感器的空白。IceCube是一個(gè)展示883 GHz云輻射計(jì)技術(shù)立方體衛(wèi)星平臺(tái)，其主要目標(biāo)是提升未來(lái)地球科學(xué)使命883 GHz云輻射計(jì)的技術(shù)儲(chǔ)備水準(zhǔn)（TRL）。”

——來(lái)自GSFC 的Dong L. Wu,介紹了NASA針對(duì)云中冰晶觀測(cè)已經(jīng)完成實(shí)施的小衛(wèi)星項(xiàng)目——冰立方(IceCube)。據(jù)悉,IceCube為3U立方體衛(wèi)星,經(jīng)過(guò)兩年半的研發(fā),于2017年4月成功送往國(guó)際空間站,并于5月進(jìn)入軌道。IceCube中的云冰輻射計(jì)(ICIR)已經(jīng)開(kāi)始白天運(yùn)作并獲取數(shù)據(jù)。2017年6—7月,ICIR獲得的云圖清晰地展示了ITCZ分布。