供需平衡
Supply- demand balance | SWT,t = DWT,t | SWT：小麦总供给量 The total supply of wheat in the current period
DWT：小麦总需求量 The total demand of wheat in the current period |
总供给
Supply (S) | SWT,t = QPWT,t + IMWT,t + OSWT,t | QPWT：小麦生产量 Current production of wheat
IMWT：小麦进口量 Current import of wheat
OSWT：小麦期初库存 Opening stock of wheat |
生产量
Production quantity
(QP) | QPWT,t = YLDWT,t × HAWT,t | YLDWT：小麦单产 Wheat yield
HAWT：小麦收获面积 Wheat harvested area |
单产
Yield (YLD) | YLDWT, t = w1Ym, WT, t +w2Yi, WT, t + w3Yma, WT, t | Ym, WT、Yi, WT、Yma, WT：小麦气象单产、投入单产和管理单产
Current wheat meteorological yield, input yield and management yield
w1、w2、w3：小麦Ym、Yi、Yma单产对应的赋值系数
Corresponding value coefficients of Ym、Yi、Yma of wheat |
气象单产
Meteorological yield
(Ym) | Ym, WT, t = w1YTm, WT, t + w2YSm, WT, t+ w3YPm, WT, t | YTm, WT、w2YSm, WT、w3YPm, WT：小麦温度单因素气象单产、日照单因素气象单产以及降水量单因素气象单产
Current wheat temperature single factor meteorological yield, sunshine single factor meteorological yield and precipitation single factor meteorological yield
w1、w2、w3：小麦3个气象单因素模型对应的赋值系数
Corresponding value coefficients of each meteorological yield model |
投入单产
Input yield
(Yi) | ${{Y}_{i,WT,t}}=\log ({{\alpha }^{Yi}}+\beta _{1}^{{{Y}_{i}}}\ln {{P}_{t-1}}+\beta _{2}^{{{Y}_{i}}}\times $
$\ln CE_{t}^{\varepsilon }+\beta _{3}^{{{Y}_{i}}}\ln FE_{t}^{\varepsilon }+\beta _{4}^{{{Y}_{i}}}\ln FI_{t}^{\varepsilon })$ | Pt-1：小麦上一期价格 Wheat price in the previous year
CEεt：成本收益情况因素向量 Cost-benefit factor vector
FEεt：费用和用工情况因素向量 Cost and employment factor vector
FIεt：肥料投入因素向量 Fertilizer input factor vector |
管理单产
Management yield (Yma) | Yma,WT,t=(1+γt)×YLD′WT,t
| YLD′WT：小麦基础单产 Wheat basic yield
γ：管理因子赋值系数 Management factor assignment coefficient |
面积
Harvested area
(HA) | HAWT,t=(w1HAcompetition,t+w2HAsurvey,t+ w3HArs,t)-kADt | HAcompetition：小麦价格竞争面积 Price competition area of wheat
HAsurvey：小麦调查面积 Survey area of wheat
HArs：小麦遥感面积 Remote sensing area of wheat
w1、w2、w3：小麦三种预测面积对应的权重系数
Corresponding value coefficients of each harvested area model
AD：小麦的成灾面积 Disaster area of current wheat
k：灾情指数,在0—1之间的一个数值,越大表示灾情越严
Disaster index, a value between 0—1, the greater the severity of the disaster |
价格竞争面积
Price competition area(HAcompetition) | lnHA competition, t= α+β1lnHAcompetition,t-1+ β2lnPt-1+β3lnPsubs,t-1 | HAcompetition,t-1：小麦上一期播种面积 Wheat harvested area in the previous year
Pt-1：小麦上一期价格 Wheat price in the previous year
Psubs,t-1：竞争相关性作物的上一期价格
Price of competitively related crops in the previous year |
调查面积
Survey area
(HAsurvey)
| $H{{A}_{survey,t}}=(\sum\limits_{i=1}^{n}{{{w}_{i}}\times H{{A}_{i,survey,t}}})\times k\times \frac{1}{r}$ | HAsurvey：调查得出的某地区小麦面积 Surveyed area of wheat in a certain area
HAi,survey：某地区第i个村的小麦调查面积
Surveyed area of wheat in the i-th village in a certain area
wi：第i个村的权重 Weight of the i-th village
k：某地区调查县所有村数量与抽样框包含的所有村数量的比值
The ratio of the number of all villages in a survey county to the number of all villages included in the sampling frame in a certain area
r：国家调查县小麦面积占全省所有县小麦面积的比率
The ratio of the area of counties under national survey to the area of all counties in the province |
预测变量
Predicted variable | 模型方程形式
Model equation form | 变量说明
Variable description |
进口量
Import
(IM)
| lnIMWT,t=αWT,IM+β1WT,IMlnQPWT,t+
β2WT,IMlnPWT,IM,t+β3WT,IMlnXRt | IMWT：小麦进口量 Wheat import
QPWT：小麦生产总量 Total wheat production
PWT,IM ：以当地货币计价的小麦进口价格 Import prices of wheat in local currency
XR：人民币对美元汇率 RMB against the U.S. dollar
αWT,IM：小麦进口量误差项 Errors of wheat import |
期初库存
Opening stock (OS) | OSWT,t= ESWT,t-1
| ESWT,t-1：上一期小麦期末库存 The ending stock of wheat in the previous period |
总需求
Demand (D) | DWT, t = QCWT, t + EXWT, t + ESWT, t | QCWT：小麦消费量 Wheat consumption
EXWT：小麦出口量 Wheat export
ESWT：小麦期末库存 Ending stock of wheat |
消费量Consumption quantity(QC)
| QCWT, t = FCWT, t + ICWT, t + FECWT, t + SECWT, t + WWT, t | FCWT：小麦口量消费量 Food use consumption of wheat
ICWT：小麦工业消费量 Industrial consumption of wheat
FECWT：小麦饲用消费量 Feed use consumption of wheat
SECWT：小麦种用消费量 Seed use consumption of wheat
WWT：小麦损耗 Wastage of wheat |
口粮消费量
Food use consumption
(FC) | FCWT, t = PCWT, rural, t × POPWT ,rural, t + PCWT, urban, t × POPWT, urban, t | PCWT, rural ：农村人均小麦口量消费量 Rural per capita FC of wheat
POPWT, rural：农村总人口数 Total rural population
PCWT, urban：城镇人均口量消费量 Urban per capita FC of wheat
POPWT, urban：城镇总人口数 Total urban population |
农村人均口粮消费量
Rural per capita consumption (PCrural) | PCWT,rural,t=exp(α1lnDPIWT,rural,t+
α2lnPRT, t+α3lnPWT, t+α4lnPMA,t+ α5lnPSB, t+b) | DPIWT, rural：农村人均可支配收入 Rural per capita disposable income
PRI：稻米均衡价格 Rice equilibrium price
PWT：小麦均衡价格 Wheat equilibrium price
PMA：玉米均衡价格 Corn equilibrium price
PSB：大豆均衡价格 Soybean equilibrium price |
| 城市人均口粮消费量Urban per capita consumption (PCurban) | PCWT, urban,t=exp(α1lnDPIWT,urban,t+ α2lnPRT, t+α3lnPWT, t+α4lnPMA,t+ α5lnPSB, t+b) | DPIWT, urban：城镇人均可支配收入 Urban disposable income per capita |
饲用消费量
Feed use consumption
(FEC) | FECWT, t = FERWT, 1×(QPPK, t + QPBV, t + QPMU, t) +FERWT, 2×QPPT, t + b | QPPK：猪肉产量 Pork production
QPBV：牛肉产量 Beef production
QPMU：羊肉产量 Mutton production
QPPC：禽肉产量 Poultry production |
工业消费量
Industrial consumption
(IC) | ICWT,t = exp (alnGDP + b) | GDP：国内生产总值 Gross Domestic Product |
种用消费量
Seed use consumption
(SEC) | SECWT, t = SPMWT, t × HAWT, t | SPMWT：每亩小麦种子用量 Wheat seed dosage per acre |
损耗
Wastage (W) | WWT, t = KLWWT, t ×QPWT, t | KLWWT：小麦损耗率 Wheat loss rate |
出口量
Export (EX) | lnEXCHN,WT,t=α1WT,EX+β1WT,EX× lnEXCHN,WT,t-1 +β2WT,EX×
ln FOBCHN,WT,t | EXCHN,WT,t：全国小麦出口量 National wheat export
EXCHN,WT,t-1：上一期全国小麦出口量 National wheat exports in the previous period
FOBCHN,WT,t：以当地货币计价的小麦离岸价格 FOB price of wheat in local currency |